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"r; '4 31'5“" f'h‘. .7.;—g ili§ -1 351:1? . ,1: 32V? [73' {.3 TV ”can . “‘1 LIfiRjARY Miss. Igan State University PLACE IN RETURN BOX to remove this checkout from your record. To AVOID FINES return on or before date due. MAY BE RECALLED with earlier due date if requested. DATE DUE DATE DUE DATE DUE 11/00 chIRCJDahDuepSS—p.“ STUDIES ON THE RELATIONSHIP AMONG SEED QUALITY TESTS AND FIELD EMERGENCE OF SUGAR BEETS (Beta vulgaris L.) IN MICHIGAN By Marcos De Dimas Morales-Barrios A THESIS Submitted to Michigan State University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Department of Crop and Soil Sciences 2000 ABSTRACT STUDIES ON THE RELATIONSHIP AMONG SEED QUALITY TESTS AND FIELD EMERGENCE OF SUGAR BEETS (Beta vulgaris L.) IN MICHIGAN By Marcos De Dimas Morales-Barrios Two experiments to evaluate differences in sugar beet seed vigor and the influence of seed size on seed/seedling vigor and performance were carried out both in laboratory and field tests in 1998 and 1999. Experiment One utilized seed lots with a wide range of seed quality, representing different production years and lengths of storage. Seed lots for Exp. 2 were of high quality representing three varieties with three different seed sizes. Laboratory tests used to evaluate seed quality and vigor included standard pleated germination test, cold test, the high moisture cold test, standard accelerated aging test, accelerated aging test incubated over NaBr, sand test, and bulk conductivity test. Field emergence data were collected at Saginaw, Ingham and Huron counties in 1998 and in Saginaw and Ingham counties in 1999. No single vigor test had the best correlation with field emergence over all planting environments. Combinations of tests in multiple regression equations, for each soil environment resulted in R2 values between 0.486 and 0.980. The use of the pleated germination test plus the cold test gave the best indication of potential field emergence under most field conditions found in Michigan. DEDICATION To all those who believed in me... Specially to Mr. Cal Bn'cker for all his support, inputs and commitment to this research, Cal with all my respect, admiration and appreciation this work is dedicated to you... ACKNOWLEDGMENTS I would like to thank my Lord for all the wonderful opportunities I have enjoyed in life; a wonderful family and this unique experience at Michigan State University. I also would like to acknowledge the Morales family for teaching me how to be a good Christian and human being and for their eternal support throughout my graduate studies. Furthermore, thank you for teaching me to fight for what I believe in and want from life. Thanks for many years of a wonderful childhood and giving me the pleasure and joy to have brothers and a sister in which every one of them are a good example for our society. I extend my sincerest gratitude to my committee members: Dr. Lawrence Copeland, Dr. Donald Christenson, Dr. Kenneth Poff, and Dr. Irvin Widders. Dr. Copeland, I am very grateful for your guidance and for accepting me as a student despite your retirement plans. You always kept your promise to be more than a professor, but also a father. Dr. Christenson, thanks for your guidance, your interesting exchange of ideas and allowing me to use this research project as the basis for my MS degree. Dr. Widders, thanks for your sincere effort to provide this research with excellent ideas and to always show an appreciation for Latin culture. Dr. Poff, you were instrumental in my obtaining this MS degree. Thank you for your commitment to the endeavor of ensuring that minority students excel in the "world of science." The Minority Summer Research Program in the Plant Sciences being just one example of such a commitment. This program provided me with the opportunity to pursue a graduate degree. Your dedication to enhancing the number of minorities in the Plant Sciences is admirable! Dr. Frank Dennis, Dr. Randolph Beaudry, and Dr. Eric Hanson, the summers that I spent working in your research projects instilled in me an intellectual curiosity and drive to pursue an MS in Plant Sciences. Dr. Dennis, I greatly appreciate your conversation with Dr. Copeland in which you convinced him of my qualifications and potential to perform with excellence at Michigan State University, regardless of the results of my Graduate Record Examination (GRE). My deepest gratitude also goes to Mario Mandujano and Edward Timm for sharing their families with me and "looking out" for me in professional and personal matters as only big brothers would do. My appreciation is extended to Marcelo Queijo and Hongyu Liu for your friendship, brotherhood, assistance, suggestions, and always showing me the "quick way" to do things in the Seed Sciences. Marcelo thanks for never saying "no" to my questions even if you had to fabricate the answer (just kidding). Cal Bricker, I am thankful for your excellent work ethics, organizational skills, dedication, dependability, genuine interest in my research, and always going the extra mile. Without you these three years would have been longer. I am grateful to Gary Zehr, Bryan Long, Paul Horny, Dennis Fleischmann for all their assistance including planting laboratory tests and field trials. The USDA Unit (Dr. Mitchell McGrath, Rick Kitchen, Robert Sims, Peter Hudy, Missy Stiefel, Yi Yu, Benildo de los Reyes and Cathy Derrico), Crop and Soil Sciences staff and graduate fellows provided me with technical assistance, support, and friendship for which I am very appreciative. Kadir Kizilkaya, Douglas Karcher and Dr. Dennis Gilliland you were an integral part in the successful completion of the statistical analysis for this project. I am also very grateful to Monitor Sugar Company, Michigan Sugar Company and Seed Systems Inc. for their funding, support and collaboration throughout this research project. Friends; Hector Ayala, Joaquin Chong, Vladimir Ferrer, Benjamin Griffin, Sandra Lopez, Edda Martinez, Carmen Medina, Diana Morrobel, Marcel Montanez, Michael Roberts, Lycely Sepulveda and Edwin Toledo, thanks for being there during the bad times because anyone is willing to take part in the good times. Thank you also for being my family throughout the years at MSU. This master's degree would not have been possible without you. Ms. Jane Thompson helped me to be passionate for God and life, and enjoy every moment. She taught me that the only obstacle to fulfilling dreams and goals is death. Thanks to Brittany Biondo, the Biondo and Hammel families for opening the doors to their loving homes and allowing me to feel welcomed and part of your family, particularly during those special days that I typically would have shared with my family. Finally, I am very proud of the professional accomplishments of Puerto Rican community at MSU. Thanks for maintaining a sense of culture even though MSU is miles away from our homeland. vi TABLE OF CONTENTS LIST OF TABLES LIST OF FIGURES LIST OF APPENDIX TABLES INTRODUCTION LITERATURE REVIEW Seed and Seedling Vigor Seed Quality and Vigor Testing Seed Size Varieties Sofl Environmental Factors Plant Depth/Spacing Seedling Diseases Seed Treatment Economic Impact MATERIALS AND METHODS Plant Material Description of Laboratory Tests Pleated Germination Test Cold Germination Test High Moisture Cold Test Accelerated Aging Test Saturated Accelerated Aging Test Conductivity Test Sand Test Experiment 1 (Seed Quality) A. Seed Lots B. Laboratory Tests vii Page xiii xiv 10 10 12 13 14 16 20 22 23 23 24 25 25 26 26 28 29 29 29 C. Field Study Experiment 2 (Seed Sizes) A. Seed Lots B. Laboratory Tests C. Field Study Experiment 3 (Seed Enhancement) A. Seed Lots B. Laboratory Tests C. Field Study RESULTS AND DISCUSSION I. Laboratory Tests A. Means and Coefficients of Variance 8. Simple Coefficients of Determination Il. Relationship Between Laboratory Test and Field Emergence A. Simple Coefficients of Determination B. Stepwise Multiple Regression Analysis III. Influence of seed size in germination and field emergence (Exp. 2) A. Laboratory Tests B. Field Emergence IV. Influence of Seed Treatment on Field Emergence (Exp. 3) SUMMARY l. Laboratory Tests II. Relationship Between Laboratory Tests and Field Emergence III. Influence of Seed Size on Germination and Field Emergence IV. Influence of Seed Treatments on Field Emergence CONCLUSIONS APPENDIX REFERENCES viii 30 33 33 33 33 35 35 35 38 38 B363 67 67 67 68 79 80 81 SSS LIST OF TABLES Table Description of Tables Page Table 1. Seed lots tested in Exp. 1 (Seed Quality) in 1998. 29 Table 2. Seed lots tested in Exp. 1 (Seed Quality) in 1999. 30 Table 3. Farm, soil series and planting dates for field studies 31 of sugar beet seed lots in 1998. Table 4. Soil series, counting dates and days after planting for field 32 studies of sugar beet seed lots in 1998. Table 5. Farm, soil series and planting dates for field studies of 32 sugar beet seed lots in 1999. Table 6. Description of nine seed lots in Exp. 2 (Seed Size) in 1998. 33 Table 7. Organism index values for the three sites for Exp. 3 (Seed 37 Quality) in 1999. Table 8. Mean, coefficient of variance and range of laboratory test 39 results averaged over all seed lots tested, Exp. 1 (Seed Quality), 1998. Table 9. Mean, coefficient of variance and range of laboratory test 40 results averaged over all seed lots tested, Exp. 1 (Seed Quality), 1998. Table 10. Mean, coefficient of variance and range of laboratory test 41 results averaged over all seed lots tested, Exp. 2 (Seed Size). Table 11. Mean, coefficient of variance and range of seed treatment 42 test results, Exp. 3 (Seed Enhancement). Table 12. Laboratory test results for the 20 seed lots in Exp.1 (Seed 44 Quality), 1998. Table 13. Table 14. Table 15. Table 16. Table 17. Table 18. Table 19. Table 20. Table 21. Table 22. Table 23. Laboratory test results for the 20 seed lots in Exp.1 (Seed Quality), 1999. Laboratory test results for the nine seed lots tested in Exp. 2 (Seed Size). Laboratory test results for the five seed treatments in Exp. 3 (Seed Enhancement), 1998 and 1999. Simple coefficients of determination r2 among laboratory test results for Exp. 1 (Seed Quality), 1998. Simple coefficients of determination r2 among laboratory test results for Exp. 1 (Seed Quality), 1999. Simple coefficients of determination r2 among laboratory test results for Exp. 2 (Seed Size). Simple coefficients of determination r2 between laboratory test results and % field emergence as influenced by location for Exp. 1 (Seed Quality), 1998. Simple coefficients of determination r2 between laboratory test results and % field emergence as influenced by location for Exp. 1 (Seed Quality), 1999. Simple coefficients of determination r2 between laboratory test results and % field emergence as influenced by location for Exp. 2 (Seed Size), 1998. Simple coefficients of determination r2 between laboratory test results and % field emergence as influenced by location for Exp. 2 (Seed Size), 1999. Independent variables significantly contributing (p50.05) to a stepwise multiple regression equation of laboratory test and the dependent variable % field emergence (mean of all sowing occasions) and the coefficients of multiple coefficients of determination for these equations, as influenced by location for 1998, Exp. 1 (Seed Quality). 45 46 46 50 51 52 55 56 57 58 62 Table 24. Table 25. Table 26. Table 27. Table 28. Table 29. Table 30. Independent variables significantly contributing (p50.05) to a stepwise multiple regression equation of laboratory tests and the dependent variable % field emergence (mean of all sowing occasions) and the coefficients of multiple coefficients of determination for these equations, as influenced by location for 1999, Exp.1 (Seed Quality). Independent variables significantly contributing (p50.05) to a stepwise multiple regression equation of laboratory tests and the dependent variable % field emergence (mean of all sowing occasions) and the coefficients of multiple coefficients of determination for these equations, as influenced by location for 1998, Exp. 2 (Seed Size). Independent variables significantly contributing (p50.05) to a stepwise multiple regression equation of laboratory tests and the dependent variable % field emergence (mean of all sowing occasions) and the coefficients of multiple coefficients of determination for these equations, as influenced by location for 1999, Exp. 2 (Seed Size). Multiple coefficients of determination (R2) for regression equations having Pleated Test 10-d count and Cold Test 10—d count as the independent variables predicting % field emergence for Exp. 1 (Seed Quality). Multiple coefficients of determination (R2) for regression equations having Pleated Test 10-d count and Cold Test 10-d count as the independent variables predicting % field emergence for Exp. 2 (Seed Size). Seedling germination as influenced by seed size and variety in laboratory tests. Seedling emergence as influenced by seed size, variety, location and days after planting in1998. xi 62 63 63 64 69 70 Table 31. Seedling emergence as influenced by seed size, variety 71 and time of planting in 1999. xii Figure Figure 1. Figure 2. Figure 3. LIST OF FIGURES Description of Figures The effect of seed size on conductance for the three varieties tested on Exp. 2. Influence of seed treatments and time of planting on field emergence for Exp. 3 in 1998 Effect of seed treatments on seedling emergence from soils infested with different level of Aphanomyces spp. xiii Page 49 73 77 Table Table A1 . Table A2. Table A3. Table A4. Table A5. Table A6. Table A7. Table A8. LIST OF APPENDIX TABLES Description of Tables Analysis of variance for the pleated germination, cold and sand test results for Exp. 1 (Seed Quality), 1998 as influenced by variety, time of count and replication. Analysis of variance for the accelerated aging test results for Exp. 1 (Seed Quality), 1998 as influenced by variety, time of count and replication. Slicing procedure for the interaction effect between variety and time of count for the pleated germination test in Exp. 1 (Seed Quality), 1998. Slicing procedure for the interaction effect between variety and time of count for the cold test in Exp. 1 (Seed Quality), 1998. Slicing procedure for the interaction effect between variety and time of count for the accelerated aging test in Exp. 1 (Seed Quality), 1998. Slicing procedure for the interaction effect between variety and time of count for the sand test in Exp. 1 (Seed Quality), 1998. Analysis of variance for the pleated germination, cold, high moisture cold and conductivity test results for Exp. 1 (Seed Quality), 1999 as influenced by variety, time of count and replication. Analysis of variance for the pleated germination, cold, high moisture cold and sand test results for Exp. 2 (Seed Size) as influenced by variety, seed size, time of count and replication. xiv Page 87 87 88 89 90 91 92 92 Table A9. Table A10. Table A1 1. Table A12. Table A13. Table A14. Table A15. Table A16. Table A17. Table A18. Analysis of variance for the pleated, cold and sand test results for Exp. 2 (Seed Size) as influenced by variety, seed size, time of count and replication. Slicing procedure for the interaction effect between variety and seed size for the pleated germination test in Exp. 2 (Seed Size). Slicing procedure for the interaction effect between variety and germination time for the sand test in Exp. 2 (Seed Size). Slicing procedure for the interaction effect between variety and aging time for the accelerated aging test in Exp. 2 (Seed Size). Slicing procedure for the interaction effect between variety and time of aging the accelerated aging test over NaBr in Exp. 2 (Seed Size). Analysis of variance for pleated germination and cold test results for Exp. 3 (Seed Enhancement) in 1998 as influenced by treatment, time of count and replication. Analysis of variance for pleated germination and cold test results for Exp. 3 (Seed Enhancement),1999 as influenced by treatment, time of count and replication. Multiple comparison and mean separation for the conductivity test in Exp. 2 (Seed Size). Multiple comparison and mean separation for the different planting dates and stand counts conducted in Exp. 3 (Seed Enhancement), 1998. Multiple comparison and mean separation for the different sites and stand counts conducted in Exp. 3 (Seed Enhancement), 1999. 93 94 94 95 95 96 100 Table A19. Table A20. Daily maximum and minimum soil temperatures (°C) and precipitation (mm) at the three field testing locations in 1998. Daily maximum and minimum soil temperatures (°C) and precipitation (mm) at the three field testing locations in 1999. 102 104 INTRODUCTION Sugar beets are an important agronomic crop in Michigan, accounting for 10.2% of the United States production in 1997. Over 71,000 hectares were planted in 1998, representing an eight percent increase from the previous year. While the cost of sugar beet seed is only about eight percent of the total production costs per hectare, the results of planting poor quality seed are more costly. Replanting costs of $70-$75 ha, along with the increased labor, soil compaction, and possible decrease in yield due to delayed planting can drastically reduce the net income from a sugar beet crop. Recommendations for early planting and increased acreage of sugar beets in Michigan is thought to have increased the possibility of poor field emergence resulting from the planting of low quality seed. The lack of emergence of sugar beet seedlings and of successful stand establishment are often major factors limiting sugar beet production. Seedling emergence requires the utilization of stored seed reserves to produce elongation of both the hypocotyl and radicle. Energy supply and seedling development are a result of catabolism and metabolism that are influenced by the soil environment. The state of the soil environment determines the efficiency of energy conversion into the expansive growth of the plant axis. During the many years in which multigerm seed was planted, no particular germination problems were encountered, unless the seed was damaged by insects. However when monogerm seed was introduced in the early 1950’s, both germination and field emergence were reduced due to the nature of the single germ seed type. This has led many growers and agronomists in the sugar beet industry to question the fundamental quality of monogerm relative to multigerm seed. Commercial sugar beet seed is now routinely processed and graded to give a standard germination exceeding 90.0%. Field emergence, however, is often much lower than that potential. Consequently, accurate ways are needed to predict the performance of individual sugar beet seed lots in the field. Because of similar concerns in a wide range of crops, vigor tests to supplement the standard germination test have been frequently suggested by seed companies and growers because of the tendency for the standard germination test to overestimate field performance under most planting conditions (Delouche and Baskin, 1973; Delouche and Coldwele, 1960; Woodstock 1973; Yacklich et. al, 1979; Kraak et. al, 1984; and Lovato and Cogalli, 1992). The many different factors that affect vigor and the variable conditions under which vigor tests may be performed in different seed laboratories, as well as the infinite array of seedbed conditions into which sugar beet seed is planted, have confounded research efforts to determine which vigor tests best predict field emergence results. This study was initiated with three major objectives: First, to evaluate which of several established seed testing procedures best determines field emergence and stand establishment in seedbed conditions in Michigan. The second objective was to determine seed quality levels of seed lots from various years and varieties and evaluate their performance in field emergence and stand establishment. The final objective was to evaluate the effect of seed size and chemical seed treatments on seed/seedling vigor and field performance. LITERATURE REVIEW Seed and Seedling Vigor Seed scientists have for many years accepted the concept of seed/seedling vigor as a seed quality factor. Within the last three decades it has also become a vital part of the quality control and marketing programs of many commercial seed companies. According to Perry (1972), one of the earliest recognitions of vigor differences in seed was by Nobbe in 1876, who used the term "energy of germination." However, most of the research on vigor and vigor testing has been done in the last 35 years. In 1950, Franck used the term "vigor" in describing his work with soil germination tests at a meeting of the lntemational Seed Testing Association (ISTA) (Perry, 1972). Seven years later Isley (1958) talked to members of the Association of Official Seed Analysts (AOSA) about vigor and vigor testing. Since then a great many papers have been published on this subject. The expression of vigor can be described from two different viewpoints. Some researchers speak of seed vigor per se as an intrinsic property of the seed (Woodstock, 1973). Perry (1972) referred to vigor along with viability, seed health, structural soundness and size as seed quality components. Heydecker (1972) concluded that a population of seeds cannot be classified as being only good or bad, but in having a level of vigor that provides a continuum from poor to good. The vigor of harvested seeds in storage has been called storage vigor (Heydecker, 1969), the vigor of the storage life of the seed (Bradnock, 1975) and the non-active vigor state (Heydecker, 1972). Descriptions of the totality and speed of germination in the absence of environmental influences have included the terms germination vigor (Heydecker, 1969), germination energy (Moore, 1963), germination capacity (Schoorel, 1956) and the intensity factor (Woodstock, 1969). These terms imply the importance of seed viability in describing seed vigor. Delouche (1974) concluded that vigor only relates to viable seeds, because a seed that does not germinate has no vigor potential. The results of the interaction between the seed/seedling and environmental influences such as temperature, moisture, soil crusting and pathogenic microorganisms is the second way vigor can be expressed. Vigorous seeds/seedlings have a greater capacity for germination and emergence when subjected to adverse environmental conditions. These seeds/seedlings are said to have a higher field survival rate (Heydecker, 1972), a larger environmental range factor (Woodstock, 1969) or a better stand establishment capacity (Delouche and Caldwell, 1960). Once the seedling stand is established, the seedling survival rate (Bradnock, 1975) and seedling growth can be measured. Thus, seedling vigor (Heydecker, 1969) on an individual plant basis can have a major effect on the competitive interactions between plants (Pollock and Roos, 1972) and ultimately on yield potential (Bradnock, 1975). Although the concept of seed and seedling vigor has been widely accepted, there was not a general agreement on a precise definition of vigor for many years. Investigators have defined vigor to coincide with their own understanding and experiences. lsely (1957) defined seed vigor as "the sum total of all seed attributes which favor stand establishment under favorable conditions." Building on this definition, Delouche and Caldwell (1960) stated that seed vigor is "the sum of all seed attributes which favor rapid and uniform stand establishment." Woodstock (1965) proposed that seed vigor was "that condition of good health and natural robustness in seed, which, upon planting, permits germination to proceed rapidly and to completion under a wide range of environmental conditions." Eight years later, Perry (1978) identified seed vigor as physiological property determined by the genotype and modified by the environment which governs the ability of a seed to produce a seedling rapidly in soil and the extent to which the seed tolerates a range of environmental factors." By this time a consensus was rapidly emerging on a definition of seed vigor. In 1977, ISTA defined vigor as "the sum total of those properties of the seed which determinates the potential level of activity and performance of the seed or seed lot during germination and seedling emergence (Perry, 1978)." In 1979, AOSA defined the term as "the sum total of all those properties in seeds which, upon planting, result in rapid and uniform production of healthy seedlings under a wide range of environment including both favorable and stress conditions (McDonald, 1980)." Each definition is unique, but all deal with field performance potential. Thus, this parameter is the ultimate result of vigor, regardless of whether the vigor expressed is an intrinsic seed property or a result of seed/seedling interaction with the environment. The AOSA definition of vigor was adopted for the planning and evaluation of this study. Seed Quality and Vigor Testing The first uniform method for conducting sugar beet seed germination tests was proposed by Skudema and Doxtator (1938). They suggested reporting results of tests at the end of 10 d and supplementing laboratory tests with field tests wherever possible so as to determine vigor of seedlings as well as plants. Also, the scientists suggested that the choice of germinating beet seeds at a continuous temperature of 200°C would better predict field emergence. However, field emergence of a seed lot is dependent both on seed quality (Heydecker, 1969) and upon the environmental factors encountered by the seed, including temperature (Bierhuizen and Wagevoort, 1974), availability of oxygen (COme and Tissaou, 1973), moisture (Keller, 1972), disease pressure (Baker and Rush, 1988; Rush, 1987) and sowing depth. Although a major component of seed quality is the germination capacity, it is a matter of continuing debate whether germination percentage measured under optimal conditions provides the best assessment of the performance potential of the seed in the field. Failure of germination percentage to relate to field emergence led to the term vigor. Seed lots are said to posses low vigor when field emergence is poor in comparison to other seed lots with comparable test germination percentages ('seed lot' for these studies refers to a particular amount of seed from which subsamples are drawn and used in the various tests). Differences in seed vigor caused by environmental conditions during seed development, harvesting procedures and storage conditions may exist among seed lots having similar warm (standard) germination results. Planting in a pathogen-infested seedbed under cold temperatures and/or moisture stress can magnify the expression of these vigor differences. Studies in recent years have approached the "vigor question" by trying different kinds of tests or seed treatments, including excess water stress (Perry, 1978), cold tests (Akeson and Widner, 1980; Kraak et al.; 1984), accelerated aging and conductivity tests (Kraak et al., 1984; Durrant and Loads, 1990). The good relationship between percentages of normal seedlings at the first count, i.e. from fourth to tenth day of standard germination and field performance has been noted (Orioli et al., 1979; Herzog, 1980; Orioli and Rosso, 1982). Since the development of the cold test in the 1940's, seed scientists have been searching for better ways to measure this complex quality factor called vigor. Many different types of vigor tests have been proposed. Those adopted by the seed industry have been promoted as aides to the farmer for selecting only the highest quality seed lots available and thus maximizing field stand establishment. Seed vigor is a complex concept that cannot be measured as easily as a single property like germination. Most researchers believe that no single test can adequately measure seed vigor and field performance across a wide range of seed quality and field conditions. Thus, a combination of physiological and biochemical indices has been suggested for improving the accuracy of predicting field performance of a given seed lot (Ching et al., 1977; Edje and Burris, 1971; and Egli and TeKrony; 1979). Seed Size The monogerm sugar beet "seed" is in reality an indehiscent fruit (utricle) containing a single seed with the perianth attached. A seed lot at harvest comprises a wide range of fruit size, maturity, and other characteristics because of the indeterminate growth habit of the sugar beet plant (Scott et al., 1974). Fruit of commercial seed lots are polished, graded, sorted for shape and gravity separated. The Michigan Sugar Company grades seed into four sizes, 2 (0.26 - 0.30-cm), 3 (0.30 - 0.34-cm), 4 (0.34 - 0.38-cm), and 5 (0.38 - 0.42-cm). According to Longden (1986), the most important factors that significantly affect the quality of sugar beet seed are its size and emergence capacity. Seed size has been shown to influence germination and field emergence (Lexander, 1981, Akeson, 1981). Seed grown in northern Europe was found to be larger in size compared to that grown in southern Europe due to the greater amount of cortex and not because of differences in true seed weight (Longden, 1986). Savitsky (1954) showed that with monogerm varieties, the weight of the true seed increased proportionally with the weight of the entire unconditioned fruit. With most crops, early growth is related to seed size but final yield is seldom affected (Black, 1959, Bleasdale, 1966) because inter-plant competition develops earlier between the larger plants from large seed. Large seeds had better germination and emergence compared to small seeds (Snyder and Filban, 1970) but large size did not necessarily result in good emergence since seeds produced under low temperatures were large because of thick fruit walls and did not germinate well (Lexander, 1981 ). TeKrony and Hardin (1968) claim that the major cause of variable and poor seedling emergence is the occurrence of seedless fruits (lacking ovules) and those containing underdeveloped seeds, which might be less frequent in larger seed grades if size is some index of extent of development. Scott et al. (1974) reported that seedling size and root/shoot ratio increased with increasing seed size. Furthermore, the largest seeds resulted in increased sugar yields compared to smaller ones. McLachlan (1972) also presented evidence that the size of monogerm seed had a strong positive effect on final root yield but no effect on sugar content. Although his results suggested strong maternal effects on sugar beet root yield, no conclusions were drawn on the genetic relationship between seed size and root yield. Varieties One of the largest causes of variation in emergence in sugar beets appears to be varieties, where ranges of 20.0 - 30.0% in emergence have been noted (Steen, 1987). Highly productive monogerm varieties are available, but improvements are still needed to give higher and better emergence under a wide range of growing conditions. Soil Stehlik and Neuwirth (1928) studied stand establishment as a comprehensive problem and treated the ecological soil conditions as the most important factor affecting emergence and seedling survival. The correlation between germination capacity and field emergence declines when soil conditions 10 become less favorable. Seed lots that systematically perform poorly relative to other lots of the same species when field cenditions deteriorate are by definition of lower vigor (Perry, 1978). Yonts et al. (1983) reported that soil temperatures affect the rate of emergence, but not the final number of plants which emerge. This linear relationship developed from the laboratory emergence indicates that maintenance of soil moisture tensions of less than six atmospheres would ensure an emergence rate of 60.0% or more. Hunter and Dexter (1950) reported that air-dry segmented sugar beet seeds germinated only at between 12 and 20.0% soil moisture. They observed that an additional small amount of water in contact with the seed induced germination in soils drier than the critical soil moisture of 12.0%. Hunter and Erickson (1952) plotted the minimum soil moisture percentages required for germination of seeds of various species in several soils on a moisture tension curve for each soil and found the maximum moisture tension which produced satisfactory germination was constant at 3.5- atmospheres for sugar beets. They concluded that greater attention should be paid to the soil moisture conditions when sugar beets are planted since they require considerably more moisture for germination than other crops. Another factor which may have an important influence on germination and emergence of sugar beet seedlings is soil compaction. The extent of compaction of the plow layer is mainly determined by the soil moisture content, the wheel track distribution, the number of passes by the wheels, the load on the wheels, the wheel arrangement and characteristics including the tire pressure (Ljungars, 1977). Because of its effect on aeration, compaction of the soils in the seedbed 11 undoubtedly has some effect on emergence, however, available references do not fully explain the effects of this factor. Emergence is also reduced by the presence of soil crusts that can form naturally under the effect of rain followed by drying by sun and/or wind. However, the impact of crusting can be reduced either by methods of preparing soils, removing the risk of subsequent formation of crusts, or by selecting varieties capable of exerting greater growth forces (Goyal, 1982). Environmental Factors Wind erosion is a major problem in the establishment of sugar beets in some areas. Sugar beet seedlings are more vulnerable during the establishment period when wind speed is the highest, i.e., May and June. Cultural methods that leave residues on the surface appear to have the greatest potential for combating the effects of erosion problems. Snyder and Zielke (1973) showed that the rate of imbibition of sugar beet seed was related to their sensitivity to excess water. They suggested that to obtain reliable germination and emergence data, the quantity of water available to the seed must be rigidly controlled. Wanjura and Buxton (1972) developed a systematic procedure for developing seedling emergence models. They developed a model to describe cotton seed water uptake during imbibition and hypocotyl elongation until emergence. Laboratory experiments were used to define the values of the environmentally—dependent coefficients of selected soil parameters in the model. In validation tests, the model predicted radicle emergence time within i nine 12 percent. Hypocotyl elongation was not significantly different from observed values in nine often comparisons done by the authors. Many studies suggest that the pre—emergence seedling growth stages are sensitive to very wet conditions. Thus, increased risk is associated with early sowings and many of the post-germination losses probably result from waterlogging. Possible approaches to minimize this problem include more tolerant varieties (Durrant, et al., 1984), pre-treating the seeds (Heydecker and Coolbear, 1977; Akeson, et al., 1981) and the avoidance of excessive soil compaction. Planting Depth/Spacing Yield of sugar beet is similar whether planted to stand or planted more thickly and hand thinned when grown in 55.0 to 76.0-cm rows at population density of 10,000 - 16,000 plants/ha (Fomstrom, 1980). Planting to stand (desired plant populations) has been successful in 76.0-cm rows as well as 56.0- cm rows if the plant populations are maintained (Cattanach and Schoeder, 1980; Fomstrom and Jackson, 1983; Winter and Wiese, 1977). Planting depths greater than 2.5 cm appear to reduce the emergence of sugar beet seeds (Cattanach et al., 1979; Fomstrom and Miller, 1987). Four to six percent higher emergence was obtained when using a 1.9-cm seeding depth compared to a 3.2-cm seeding depth, but the results were not always consistent (Fomstrom and Miller, 1989). Also, more sugar beet seedlings emerged and at a faster rate as the depth of seeding decreased from 4.5 to 1.6 cm. Herbicide injury to sugar beet seedlings 13 increased as depth of seeding increased to more than to 2.5 cm (Wilson et al., 1990). Seedling Diseases Stehlik and Neuwirth (1928) concluded that the most critical period during planting and stand establishment is usually from the time of seed swelling to the four-leaf stage, during which the young seedlings are very vulnerable to fungal attack. However, it is primarily the suitable ecological conditions that enable the seed to germinate and emerge. Sugar beet is susceptible to numerous seed/seedling diseases, expressed as seed decay, pre-emergence damping—off, post-emergence damping-off and infection of the radicle and hypocotyl of emerged plants. The severity of the diseases is influenced by the susceptibility of the host, the inoculum potential of the pathogen, environmental factors, (including temperature, moisture, and soil characteristics) and the effectiveness of control measures. Seedling infection by Phoma is often called "black leg." Infection by Aphanomyces is often referred as "black root." Because of possible confusion of black leg and black root and the imprecise use of these terms, use of the generic name of the pathogen is preferable in identifying seedling diseases, e.g., Pythium damping-off, Rhizoctonia damping-off, Aphanomyces (or beet water mold) seedling disease, and Phoma seedling infection. Pythium ultimum Trow is present to some extent in nearly all arable soils and attacks unprotected seedlings at all temperatures favorable for the germination of beet seed. The pathogen is favored by high moisture and attacks 14 seedlings of many other crops, causing pre-emergence damping-off. Post- emergence damping-off may follow under moist soil conditions. Pythium aphanidermatum (Edson) Fitzp., a high-temperature fungus, attacks seedlings only in warm soils with abundant soil moisture. Rhizoctonia solani Kilhn causes some pre-emergence death of seedlings but inflicts most of its damage on emerged seedlings. Infection is initiated below the soil surface and extends up the hypocotyl, with a distinct margin between infected and healthy tissue. Lightly infected seedlings often survive and may produce nearly normal roots. The same fungus, however, may later in the season cause crown rot or dry rot canker on maturing roots. Seedlings infected by Aphanomyces cochlioides Drechs. can usually be distinguished from those infected by Phoma betae or Pythium spp. because the entire hypocotyl becomes thin and black, with cotyledon necrosis at the base. Seedlings attacked but not killed by P. betae or Pythium sp. usually recover rapidly, but Aphanomyces persists and stunted plants still occur in July. The fungus can be found on the lateral roots of beet plants in infested fields throughout the season. This disease is favored by warm, moist soil and thus occurs most often in late-sown crops. In Europe, a survey conducted by Asher and Payne (1989) of randomly selected sugar beet fields confirmed the presence of Aphanomyces cochlioides Drechs and Pythium sp. on about one-third of the fields tested. Phoma betae Frank is the only important seed-bome pathogen of sugar beet seedlings. It first appears to a limited extent in the fall as seedling or leaf 15 spot infections and persists through the winter as infections on leaf or crown tissue. With spring growth and bolting, leaf spots, crown infections and later, lesions on the seed stalks appear. During periods of rainfall or high humidity, pycnidia of the fungus exude spores in gelatinous masses. These spores are readily spread by splashing rain or overhead sprinklers or, when dry, may become air-bome and by these means, come into contact with developing floral parts and result in seed infection. However, the most important period of seed infection appears to occur during the harvest period. When the seed is ready to harvest, the seed stalks are cut, swathed and allowed to cure in the field for a period of 10 to 20 d before the actual threshing of the seed. Seed Treatment In Europe, an excellent survey by Dunning (1972) showed that plant pathologists in 13 countries believed that the most important seedling pathogen of sugar beets was Phoma betae and that effective seed treatments against this pathogen were indispensable. In the United States, however, the experience has been less consistent. Prior to the 1930's when most of the seed was imported from Europe, Phoma seedling disease was quite serious and mercury-based seed treatments such as diethyl mercuric phosphate (EMP) were commonly used as the only effective means of control. With the initiation of domestic seed production in the arid southwest, sugar beet seed was found to be essentially free from Phoma (Leach, 1940 and 1944), thus allowing attention to be focused on the soilborne seedling pathogens. After the use of mercury seed treatments was discontinued, newer often selective fungicidal seed treatments were 16 introduced. However, when domestic seed production was later shifted to Oregon for the production of non-bolting varieties, some seed lots were again found to carry considerable amounts of Phoma. Several factors prompted the reevaluation of the use of EMP. First, attitudes have hardened against the continued use of mercuric compounds. Secondly, a shorter treatment than 24 h may be adequate, since a survey of Phoma betae levels in sugar beet seed (Payne, 1986) suggests that severe infestations are rare. Thirdly, the need for improved stand establishment has been highlighted (Durrant, Jaggard and Scott, 1984), and studies (Durrant and Leads, 1984, 1987) have indicated that enhancing the seed by prolonged steeping should help to achieve more rapid establishment of an adequate number of plants. Therefore, an alternative treatment with comparable efficiency was needed. The candidate chemical, Thiram (tetra-methyl thiuram disulphide), gave maximum control of deep-seated infections in several species but only when the seed was steeped in a 0.2% suspension for 24-h at 300°C (Maude, 1966, 1986; Maude, Vizor and Shuring, 1969) and without being harmful to human health. In a series of experiments between 1977 and 1979 Byford (1985) confirmed that steeping in Thiram was as effective as EMP. Knott (1925) described soaking seed of some vegetables in water to promote germination and utilization of food reserves, the use of oxygen and the release of carbon dioxide. Some of the factors which affect this beginning of growth are, the time (length) of soaking, the temperature of the water, the relative amount of water, the movement of the water, the amount of water surface 17 exposed to air, the size of the seed and the density of the seed mass. More Injury due to the loss of soluble food reserves might be expected. However, this is not the case, probably because of the better supply of oxygen and the removal of carbon dioxide. Knott ( 1925) concluded that soaking seed of beets in shallow distilled water for 24 h shows no definite influence on later growth and yield. In 1944, Stout and Tolman concluded that synthetic growth-regulating substances did not give significant benefits to seedling emergence, vegetative growth, sucrose content, purity, or yield of roots per acre. Miyamoto and Dexter (1960) reported that monogerm seed need more moisture to germinate than multigerm seed. In another study (Dexter and Miyamoto 1959), they found moisture uptake and emergence to be accelerated if the sugar beet seed balls were coated with hydrophilic colloids. In the late 1970's and early 1980's, the so-called "crop success" that 70.0% of the seeds sown must give harvestable roots was still not achieved. Durrant and Scott (1981) stressed the possibility of improving stand establishment by making the seed more tolerant to sub-optimal conditions in the seedbed environment by treating it under controlled conditions before sowing. Such treatments have utilized various combinations of water, different salts, sugars or polyethylene glycol solutions with steeping, wetting and drying cycles, vigorous bubbling, etc. The treatments were divided into two types - those which "advance" seed (Genkel, 1946; Austin, Longden, and Hutchinson, 1969; Longden, 1971) and those which "prime" seed (Heydecker, 1974). Both treatments increase the rate of germination, however, during "advancement" all 18 seeds are affected equally so there is little effect on the speed of germination, whereas with "priming," the target is to bring all seeds to a similar physiological stage resulting in highly synchronized germination. In general, treatments utilizing water or dilute solutions "advance" seeds, while treatments with sufficiently concentrated osmotica to restrict water enough to prevent germination "prime" seeds. Although in laboratory experiments certain pre-treatments substantially improved both the speed and percentage germination, there are inconsistent effects, particularly on seedling numbers in field experiments (Heydecker and Coolbear, 1977; Longden et al., 1979), which make it difficult to evaluate the usefulness or potential of such treatments. In the late 1980's, a new method of priming was introduced termed solid matrix priming (SMP) (Taylor et al., 1988). This method controls hydration through the metric potential in contrast to traditional priming methods that employ osmotic potential. Rush (1991) confirmed that SMP promoted early emergence, suppressed pre-emergence damping-off and produced a greater final stand than osmoprimed treatments on sugar beets. However, significant suppression of post—emergence damping-off, mainly caused by P. ultimum and A. cochlioides, was not achieved by using SMP (Rush, 1992). Pelleting tends to improve flow through precision drills and also provides a convenient carrier for insecticides, fungicides and some nutrients (Dunning, et al., 1986). Until now, the principal component of the coating is a clay called ‘Filcoat’ that in the dry state has a few small pores. However, there is evidence (Vanstallen, 1971; Thompson, and Woodwark, 1975; Verveka, 1983) that under 19 very wet conditions, such coatings decrease both the rate of germination and final germination percentage and that the less vigorous seeds are probably affected most. There have been many comparisons of unpelleted and pelleted seed in field experiments, although, the results have not been consistent. However, pelleting significantly increased establishment in about ten percent of the comparisons in England (Hibbert, et al.,1975). Dunne et al. (1998), in order to satisfy both the public health and environmental concerns, presented an alternative means for disease suppression by using biological control. They found that the combined use of Pseudomonas flourescens, F113 and Stenotrophomonas maltophilia W81 protected sugar beet seedlings form Pythium-mediated damping-off as much as when chemical pesticides when added in the pelleting medium. Economic Impact In the past five years, Michigan has produced approximately 13,000,000 Mg of sugar beets, making the crop one of the most important in the state. Generally speaking, yield is the most important factor in determining net profit from sugar beet production. A profitable yield needs to be preceded by a satisfactory stand, however, it is estimated that 15.0 to 20.0% of fields need to be replanted annually due to inadequate stands (Dr. R. Zielke, Director Research, Michigan Sugar Company, Carrollton, Mich, personal communication). Poor seedling vigor and problems with seedling survival to the four-leaf stage appear to be major factors. It is estimated that loss of yield on replanted hectares is approximately 300,000 Mg of beets. Replanting costs are about $12lha and the 20 loss in yield from replanting is estimated to be more than $36lMg. Thus, the total cost of replanting is around $12 million annually to the Michigan sugar industry. Much of this loss could be prevented by greater success in sugar beet emergence, stand establishment and survival. 21 MATERIALS AND METHODS Three experiments were conducted in 1998 and 1999. In the first, results of seven different laboratory tests were compared with the field emergence of 20 seed lots. In the second, nine seed lots consisting of three different varieties and three seed sizes were further compared in laboratory and field tests in both 1998 and 1999. Finally, the effects of five different coating treatments on laboratory and field performance were evaluated on one seed lot. Plant Material: The seed lots used in the field and laboratory experiments were obtained from Michigan Sugar Co. (Caro, MI) and Monitor Sugar Co. (Bay City, MI). However, the companies that produced the seed were American Crystal Sugar Co., Betaseed (Shakoppee, MN) and Holly Hybrids (Sheridan, WY). All of the seed was conditioned to remove a fraction of the outer portion (corky layer) of the pericarp. The seed was then graded through sieve plates from sizes 2 (0.26 - 0.30-cm) through 5 (0.38 - 0.42-cm) in 0.04-cm increments. Since most of the seed lots were commercially available, they were obtained pre-treated with a commercial application of either Thiram or Apron® at the rate of 1.5 and 8 oz per 454-kg of seeds, respectively. Seed Systems Inc. (Gilroy, CA) applied all the treatments in the seed enhancement experiment. The seed lots were monogerm, a mendelian genetic trait, which produces a single seed per fruit. The seed lots were of various ages depending on the 22 year of production. A smaller number of older seed lots with poor germination (s 80%) were also selected. Description of Laboratory Tests: Laboratory tests for the three experiments in both years were performed in a randomized complete block design. The procedures for each test were identical for all the experiments, unless otherwise specified. Standard methods for analysis of variance were used to analyze the laboratory data. All data were analyzed using the SAS 7.0 Statistical Software package (SAS Institute Inc. 1998). The MIXED model procedure was used, allowing the handling of both fixed and random effects in a linear model, giving a continuous response. 1. Pleated Germination Test (PT) Seeds were soaked in deionized water overnight (16 h) in 400-ml beakers. Cheesecloth was attached to the top of each beaker with a rubber band. Immediately after the soaking period the water was decanted and the container refilled and emptied five times for complete rinsing. The seed was then placed on paper towels to dry for an hour. Pleated germination paper (Anchor Paper Co., St. Paul, MN) was placed into 12.7x17.8x12.7-cm plastic boxes containing 30 ml of deionized water. Seeds were placed between the flutes at the rate of four seeds per flute, 100 seeds per lot, two lots per box. A paper clip was placed on the paper separating the two seed lots within each box. Approximately 5 ml of additional water was added by using a misting bottle to achieve uniform wetness of the paper. The 23 boxes were sealed when the seeds were in place. Four randomized replications of each seed lot were 31 31genninated concurrently in boxes maintained at 230°C in a constant temperature room under continuous fluorescent light. Germination counts were made at 5 (PT-5) and 10 d (PT-10) after planting. Ungerminated seeds were opened with needle-nose pliers and judged to either be live or dead, based on the embryo appearance. Abnormal seedlings were not counted as germinated. 2. Cold Germination Test (CT) Seeds were soaked overnight (16 h) in 400-ml beakers and rinsed as described in the pleated paper germination test procedure, then planted in soil from the Saginaw Valley Bean and Beet Farm near Saginaw, Michigan (Misteguay soil complex having a silty clay texture) that had been passed through a 0.64-cm sieve. One kg of soil was placed into plastic boxes measuring 18x33x9 cm, then leveled to a depth of approximately 1.9 cm. Then 50 seeds were placed onto the soil using a counting board to assure equal spacing, and another 1.0 kg of dry soil was placed over the seeds. Water was added from a plastic bottle with a cap with small holes to allow even application without disturbing the soil surface. Sufficient water was added to bring the soil to 20% moisture (2/3 of moisture at field capacity). Seed containers were randomized within germination chambers, with each plastic box serving as one 50-seed replication. Two movable germination chambers were utilized to represent two replications of each seed lot. The 24 chambers were placed in a constant temperature room maintained at approximately 100°C for 4 d, then moved to a constant temperature room maintained at 230°C for the duration of the test. Finally, three open plastic containers were used to add deionized water to the top, middle and bottom part of the chambers to assure high relative humidity. Germination counts were made at 5 (CT-5) and 10 d (CT-10) of incubation at 230°C. Seedlings were removed from each box after counting. Upon completion of the final count, the soil was air dried for a short time by passing it again through a 0.64-cm sieve and allowing it to dry. After mixing, the soil was again weighed into the boxes and the test repeated. 3. High Moisture Cold Test (C THM) This test was similar to the CT, except that soil at 35% moisture was used and germination counts were made at 3 and 6 d instead of 5 and 10 d. 4. Accelerated Aging Test (AA) The initial seed moisture content was determined by weighing 5.0 g of each seed lot (fresh weight) and drying in an oven at 105.0°C for 2.5 h; then the seeds were reweighed (dry weight). If the seed moisture content was greater than 14.0%, the seeds were dried to 10-14% moisture before the aging test (AOSA). The plastic accelerated aging boxes (11.0x11.0x3.5-cm) and the wire- mesh trays (10.0x10.0x3.0 cm) were washed in a 15.0% sodium hypochlorite solution (Clorox) and then dried. Forty ml of water were added to each. Then a 25 dry wire-mesh tray with approximately 17.0 g of sugar beet seeds in a uniform layer was placed in each plastic box which was then sealed by placing a Vaseline layer over the lid corners. The accelerated aging oven chamber was set at 41 .0°C for 12 h before the test. Then plastic boxes were placed on a shelf spaced approximately 2.5 cm apart and held at 410°C for 72 h with the door continuously closed to prevent temperature fluctuations. After the aging period, the plastic boxes were removed and cooled to room temperature for an hour before planting the seeds in pleated germination tests. Germination was evaluated at 2 (AA-2) and 4 d (AA-4) after planting. 5. Saturated Accelerated Aging Test (AANaBr-2 and AANaBr-4) This test was similar to the AA test, except that 60 ml of NaBr saturated solution was added to each plastic box (11.0x11.0x3.5 cm) to maintain the relative humidity at about 54.0%. All solutions were saturated at 41 .0°C (Jianhua, and McDonald, 1996). 6. Conductivity Test (COND) Prior to initial use, the conductivity meter was calibrated using a potassium chloride solution. To calibrate the dip cell of the conductivity meter, 0.745 g of pure analytical grade potassium chloride (dried at 150.0°C for 1 h and cooled in a desiccator before weighing) was dissolved in 1 L of deionized water to make a 0.01M KCI solution, giving a 1 - 5 uS cm‘1 which was slightly higher than the 1.27tt8cm" (at 230°C) expected because of the low conductivity of the 26 deionized water. If the reading was incorrect, the calibration test was repeated and the meter adjusted. The initial seed moisture content was determined by weighing 5.0 g of each seed lot (fresh weight) and drying in an oven at 105°C for 2.5 h; then the seeds were reweighed (dry weight). All seed lots had a seed moisture content of 11 - 14%. Fifty ml of deionized water was placed in 50-ml flasks which were covered with aluminum foil to prevent dust contamination and equilibrated at 230°C for approximately 24 h prior to placing the seeds in the water. A control flask containing only deionized water was included to monitor water quality. Four subsamples of 75 treated seeds each were weighed and placed in the 50-ml flasks containing the deionized water (75 seeds per flask). Each flask was gently swirled for ten seconds to ensure that all seeds were completely immersed. Flasks containing water and seeds were recovered with aluminum foil prior to being placed at 230°C for 24 h. Immediately following the end of the 24-h soaking period, the conductivity of the water in the flasks was measured at 230°C. The flasks (with seeds) were swirled for 10 s, the foil removed and the conductivity 018 cm") determined by immersing a pipette-type cell into the solution without filtration. Direct contact of the cell with the seeds was avoided and the dip cell was rinsed twice with deionized water between samples. All hard seed (floating) observed during the test were removed, surface dried, weighed, and the weight subtracted form the 27 initial weight of the 75-seed subsample. All the conductivity evaluations were made inside the 230°C chamber to avoid temperature fluctuations. 7. Sand Test (ST) Seeds were soaked overnight (16 h) in 400-ml beakers and rinsed as described in the pleated paper germination test procedure, then planted in blast silica sand (Magnum Blast co.). First, 1.0 kg of sand was weighed in a plastic bag and 40 ml of deionized water added to give four percent moisture. The sand and water contained in the plastic bag were mixed for approximately one minute to ensure even moisture distribution in the sand. The sand (1.0 kg) was placed in18.0x33.0x9.0-cm plastic boxes and leveled to a depth of approximately 1.3 cm; then 50 seeds were placed on top of the sand using a counting board to assure equal spacing. Another 1.0 kg of moist sand (4% moisture) was then placed over the seeds and leveled. Finally, plastic wrap was placed onto the boxes to prevent loss of moisture. Seed lot containers were randomized within the germination chambers. Each plastic box served as one 50-seed replication. Two movable germination chambers were utilized to provide two replications of each seed lot and placed in a constant temperature room maintained at 230°C for 10 d. Finally, 3 plastic containers with deionized water were added to the top, middle and bottom part of the chambers to assure maintenance of high relative humidity. Germination counts were made at 5 (ST-5) and 10 d (ST-10) of incubation at 230°C. Emerged seedlings were removed from each box after the first count. Upon completion of the final count, the sand was discarded. 28 Experiment 1 (Seed Quality) A. Seed Lots: Twenty seed lots representing 12 varieties and seven different years of production were used in 1998 (Table 1). Another 20 seed lots different from those used in 1998 were tested in 1999. These consisted of eight varieties representing six different production years (Table 2). B. Laboratory Tests: Six laboratory tests (PT, CT, AA, AANaBr, ST, COND) were conducted on the 20 seed lots in 1998 as previously described. All tests except AA, AANaBr, and ST were repeated in 1999. However, CTHM was conducted only in 1999. Table 1. Seed lots tested in Exp. 1 (Seed Quality) In 1998. Entry Variety Source Lot No. Year Size 1 ACH—197 Michigan 6055324 93 3 2T ACH-308 Monitor 470346 93 3 3 ACH-319 Michigan 6102320 95 3 4 Beta 5931 Michigan 6105325 96 3 5 HM E 4 Michigan 635312 92 3 8 HM E 10 Michigan 6080321 93 3 91 uswzo Michigan uncertain 93 3 1o ACH-185 Monitor 219596 91 5 1 1 ACH-185 Monitor 328404 92 4 14 ACH-197 Monitor 320207 92 2 15 Beta 5931 Monitor 214206 92 2 16 HM E 4 Monitor 336420 92 4 17 HM E 4 Monitor 324211 92 2 161 USH-20 Monitor 82032 76 4 20 USH—23 Monitor 279307 66 3 21 ACH—185 Michigan 606310 96 3 52 HM E4 Michigan 931136 93 4 54 HM E4 Michigan 93514 93 3 56 ACH-319 Michigan 950427 95 2 57 ACH-319 Monitor 950427 95 3 1' Untreated Seed. 29 Table 2. Seed lots tested In Exp. 1 (Seed Quality) in 1999. Entry Variety Source Lot No. Year Size 77 HM E10 Michigan 941025 94 4 78 ACH-319 Michigan 950514 95 2 79 ACH-319 Michigan 980027 98 3 80 HM E17 Michigan 980017 98 2 81 HM E17 Michigan 97005 97 3 82 HM E17 Michigan 980021 98 3 83 HM E17 Michigan 980019 98 3 84 ACH-555 Monitor 980444 98 4 85 ACH—848 Monitor 980285 98 3 88 ACH-555 Monitor 980444 98 2 87 HM E17 Monitor 970097 97 3 88 ACH-848 Monitor 980285 98 4 89 ACH-555 Monitor 980444 98 3 9O ACH-1353 MiIMo 980443 98 3 91 ACH-1353 MllMo 980443 98 2 92 ACH-1353 MilMo 980443 98 4 93 HM E17 Monitor 970095 97 4 94 HM E17 Michigan 980019 98 3 95 HM E17 Michigan 980015 98 2 98 HM E4 Michigan 931138 93 2 C. Field Study: 1998: Twenty seed lots were planted in three different locations. An eight-row vacuum planter was used in location one and three with a space of 76 cm between rows. A four-row Almaco belt cone planter was used for location two, with a space of 71 cm between rows. Planting depths were 1.3, 4.2 and 1.3 cm, respectively. Planting dates, locations and soil type are given in Table 3. The seed spacing was 6.4 cm at all locations. Plot length was 6.1 m for all locations. Single row plots were arranged in a randomized complete block design with eight replications. Three field emergence counts were made at each location. The number of days after planting to final emergence for each count and respective dates are shown in Table 4. 30 Single linear correlation coefficients (r) were calculated to show the association among all laboratory tests and between single laboratory tests and field emergence. The linear regression model for r was y = a + bx + 6. However, simple coefficients of determination (r2) were used to illustrate the differences. Multiple regression equations (R) were used to further explain the variability of field emergence using various laboratory tests in the same equation, rather than single linear correlation coefficients. Although the values were calculated as multiple regression equations (R), multiple coefficients of determination were used (R2) to explain the differences in results. The equation used for the multiple regression analysis was Y = (30 + (31x1 + (32X2 + 6... where Y was field emergence, X1 was the germination percentage in the pleated germination test and X2 was the percent germination in the different vigor tests and 6 was the error term that measured the deviation of a random variable from its mean. Table 3. Farm, soil series and planting dates for field studies of sugar beet seed lots in 1998. Location County Farm or Soil Planting Farmer Series Date 1 Saginaw MSU 8&8 Misteguay 4/20 silty clay 2 Ingham MSU Campus Metea 4/24 sandy loam 3 Huron Maust Kilmanagh 4/22 loam 31 Table 4. Soil series, counting dates and days after planting for field studies of sugar beet seed lots in 1998. Date Location Soll Series 1't Count 2'" Count 3'‘1 Count 1 Misteguay 5/7 5/13 5/20 (Dap)T ‘I 7 23 30 2 Metea 5/8 5/12 5/19 (Dap) 13 19 28 3 Kilmanagh 5/4 5/14 5/21 (Dap) 12 22 29 T Dap= Days after planting. 1999: The twenty seed lots were planted in three different locations using a four-row Almaco belt cone planter unit with 71-cm spacing between rows. Planting depths were 3.2, 1.9 and 1.9 cm respectively. Planting dates, locations and soil types are given in Table 5. The seed spacing was 6.4 cm and plot length was 6.1 m for all locations. Single row plots were arranged in a randomized complete block design with eight replications. Table 5. Farm, soil series and planting dates for field studies of sugar beet seed lots in 1999. Location County Farm or Sell Planting Farmer Series Date 1 Saginaw MSU 8&8 Misteguay 4/28 silty clay 2 Ingham MSU Campus Capac 4,14. 5,31 Botany loam 3 Ingham MSU Campus Metea 5/4 Crop 8. Soil sandy loam 1' Late sowing for Experiment Two. 32 Experiment 2 (Seed Sizes) A. Seed lots: Nine different seed lots were tested in both 1998 and 1999, consisting of three varieties (ACH648, ACH503, ACH555) and three seed sizes (2, 3, 4), all of which were produced in 1997. Entry number, variety, source, lot number, year of production and size are given in Table 6. Table 8. Description of nine seed lots In Exp. 2 (Seed Size) in 1998. Entry Variety Source Lot No. Year Size 58 ACH-848 Michigan 970253 97 2 59 ACH—848 Michigan 970253 97 3 60 ACH-848 Michigan 970253 97 4 88 ACH-503 Monitor 970247 97 2 89 ACH-503 Monitor 970247 97 3 70 ACH-503 Monitor 970247 97 4 71 ACH-555 Monitor 970250 97 2 72 ACH—555 Monitor 970250 97 3 73 ACH-555 Monitor 970250 97 4 8. Laboratory Tests: Seven laboratory tests (PT, CT, CTHM, ST, AA, AANaBr, COND,) were conducted throughout both 1998 and 1999 on the nine seed lots as previously described. C. Field Study: 1998: The nine different seed lots were sown in three different locations. An eight-row vacuum planter was used in locations one and three with 76 cm between rows. A four-row Almaco cone planter unit was used at location 33 two, with 71 cm between rows. Planting depths were 1.3, 4.2 and 2.5 cm respectively. Planting dates, locations and soil type are given in Table 3. Plot length was 6.1 m and seed spacing was 11.4 cm for all locations. Single row plots were arranged in a randomized complete block design. A block consisted of the nine experimental units (seed lots) and each block was replicated eight times. Three field emergence counts were made at each location. The dates and number of days after planting for each count are shown in Table 4. Simple coefficients of determination (r2) were calculated for association between laboratory and field emergence results. Multiple coefficient of determination (R2) equations were used to establish the relationship between laboratory test results and field emergence for each planting date. 1999: The nine different seed lots were planted in two different locations. However, in location two an early (4/14) vs. late (5/3) planting was used to compare the differences due to date of planting. A four-row Almaco belt cone planter unit was used for all locations, with 71 cm between rows. Planting depths were 3.2, 1.9 and 1.9 cm, respectively. Planting dates, locations and soil type are given in Table 5. A seed spacing of 10.2 cm and plot length of 6.1 m was used. Single-row plots were arranged in a randomized complete block design, with each block consisting of the nine experimental units (seed lots) and each block replicated eight times within each location. 34 Experiment 3 (Seed Enhancement) A. Seed Lots: 1998: One seed lot of variety HM E-17 produced in 1995 was selected for this study. Five seed treatments were compared with the current treatment, Celpril, as treatment number one. This gives a film-coated treatment of the fungicide Tetramethylthiuram disulfide, often known as Thiram®, along with a dye to color the seed. The second treatment was a pelleted treatment containing the fungicide, but no additional treatment (Plain Pellet). The third was a pelleted seed that had been conditioned by a process referred to as priming advanced treatment (PAT), a patented priming process to enhance speed of emergence. During conditioning, PAT seed undergoes removal of germination inhibitors as well as sophisticated control of moisture and temperature to promote the very early stages of embryonic development. The fourth treatment consisted of pelletized seed with the fungicide Tachigaren® added (TACH) to control the seedling diseases caused by the soilborne Aphanomyces fungi. The fifth treatment utilized a pelleted seed combining the PAT process plus Tachigaren® (PAT + TACH). A second seed lot of HM E-17 produced in 1996 (as opposed to 1995) was selected in 1999; otherwise, all the seed coating techniques used were the same. 8. Laboratory Tests: Two laboratory tests (PT, CT) were conducted on the five seed lots in 1998 and 1999 as previously described. 35 C. Field Study: 1998: Field plots were planted at the Saginaw Valley Bean and Beet Farm near Saginaw, Michigan on a Misteguay silty clay soil. All plots were planted with a John Deere-71 plate planter unit mounted on a tool bar adapted for the three-point hitch attachment to a tractor. Single row plots 12.2 m long were arranged in a randomized complete block design with six replications but were planted at 71 cm between rows. Seed was spaced at a distance of 10.2 cm and a depth of 1.9 cm. An early (4/15) vs. late (5/15) planting was conducted to compare the differences due to planting date. Emergence was measured seven times for each planting date. A simple two-way analysis of variance (ANOVA) was used to determine differences among treatments. However, correlation or multiple regression analysis was not performed due to the lack of data points. 1999: Field plots were again planted at the Saginaw Valley Bean and Beet Farm. However, three sites with different disease pressure were Chosen within the farm. The area with low disease pressure had not had sugar beets grown in the field for more than 25 years. The medium field location had a rotation in which sugar beets were grown every three years. The high disease pressure field had a history of diseases and was one in which sugar beets had been grown in both 1997 and 1998. Soil samples from the three sites were sent to the Plant Disease Clinic at the University of Minnesota and assayed for the presence of Aphanomyces sp. and other root rot pathogens. The disease index for the three sites is provided in Table 7. A late planting date (5111) was chosen 36 to provide optimum conditions for disease development. Type of planter, plot length, row space and seed spacing were the same as that used in 1998. Table 7. Organism index values for the three sites for Exp. 3 (Seed Enhancement) in 1999. Site Organism lndex'I' Classification 1 3 Low 2 28 Medium 3 94 High T Values fall between 0 and 100. A value of 0 means that no disease was detected. A value of 100 means that roots of all plants were severely rotted or that all seedlings died in the greenhouse bioassay. Planting depth was increased to 2.5 cm to attain a more uniform plant stand because of more optimum moisture for germination. A single block consisted of the five treatments repeated four times. Emergence was measured four times at 9, 14, 17 and 21 d after planting for all sites. A simple two-way analysis of variance was used to determine the differences between treatments. 37 RESULTS AND DISCUSSION I. Laboratory Tests A. Means and Coefficients of Variance The highest mean emergence of 92.5% occurred for the 10-d pleated germination test for the Exp. 1 (Seed Quality) in 1998 (Table 8). On the other hand, the lowest mean germination (13.7%) occurred at the 2-d accelerated aging test for the same experiment. The difference between the 10d pleated germination (PT-10) and the 10-d cold test (CT-10) results was 13.1% for Exp. 1 in 1998. A difference of 13.0% germination occurred between means of the 10-d sand test (ST-10) and PT-10. A similar difference of 15.4% occurred between results of the 4-d accelerated aging test and the sodium bromide (AANaBr—4) test, however, a larger germination difference of 56.0% occurred between the 2-d standard accelerated aging (AA-2) and PT-10 tests. In Exp. 1 in 1999 the PT-10 again produced the highest mean emergence at 94.0% (Table 9). However, the lowest mean emergence of 58.3% occurred for the 3-d cold high moisture test (CHM-3). For the same experiment, a mean difference of only 2.0% occurred between germination results for the PT-10 and CT-10. However, there was a 14.1% germination difference between the PT—10 and 6-d high moisture cold germination test (CTHM-6). Similar differences occurred in Exp. 2 (Seed Size), however, the largest difference of 78.6% occurred between PT-10 and AA-2 (Table 10). The highest mean emergence of 94.0% also occurred at the PT—10 and the lowest mean emergence occurred at the 2—d count of the accelerated aging test. In Exp. 3 (Seed Enhancement) in 1998 the highest mean of 98.6% 38 for PT-10 was shared between the advanced primed seed (PAT) and the plain pelleted seed (Plain), however, Tachigaren-treated (TACH) seed germinated only 67.0% (Table 11). All 10-d cold germination test means in Exp. 3 were above 90.0%, including Celpril treated seed at 99.0%, but were only 92.0% for PAT. However, the highest PT-10 mean germination in 1999 was from plain pelleted seed at 96.3%, and the lowest for PAT+TACH at 80.5%. In the CT-10 the Plain treatment produced the highest mean at 97.5% and the lowest was PAT + TACH at 79.5%. Table 8. Mean, coefficient of variance and range of laboratory test results averaged over all seed lots tested, Exp. 1 (Seed Quality), 1998. Lab Tests Mean CV RangeT (% germinated) PT—5 87.9 18.8 17 - 100 PT-10 92.5 9.73 59 - 100 CT-5 78.7 28.4 0 - 100 CT-10 79.4 25.5 10 - 100 ST-5 66.7 34.3 o - 100 ST-10 79.5 22.7 10 - 100 AA-2 13.7 128.0 0 - 73 M4 36.5 54.8 1 - 75 AANaBr-2 26.6 75.2 o - 80 AANaBr-4 77.1 28.2 13 - 100 COND: 480.1 16.9 299.9 - 620.5 1' The range of values is for all the replications. 1 Values for the tests are expressed as % of seed germinated, except COND that is in (18 cm "9 ". 39 Table 9. Mean, coefficient of variance and range of laboratory test results averaged over all seed lots tested, Exp. 1 (Seed Quality), 1999. Lab Tests Mean CV RangeT (% germinated) PT-5 93.2 4.6 60 - 100 PT-10 94.0 4.6 80 - 100 CT-5 90.9 7.6 62 - 100 CT-10 92.0 7.3 64 - 100 CTHM-3 58.3 41.1 0 - 92 CTHM-6 79.9 17.9 36 - 96 COND: 531.7 19.0 391.5 - 840.0 1' The range of values is from four replications. 1: Values for the tests are expressed as % of seed germinated, except COND that is in 118 cm “9 ". 40 Table 10. Mean, coefficient of variance and range of laboratory test results averaged over all seed lots tested, Exp. 2 (Seed Size). Lab Tests Size Mean CV RangeT (%jerminated) PT-S - 93.2 4.6 80 - 100 PT-10 .- 94.0 4.6 80 - 100 CT-5 - 69.9 5.1 62 - 96 CT-10 - 91.5 4.7 84 - 100 CTHM-3 - 49.1 74.6 10 - 74 CTHM-8 - 76.9 23.2 66 - 96 ST-5§ 2 55.6 21.6 30 - 70 3 70.7 14.2 56 - 66 4 71.0 46.7 52 - 62 ST—10§ 2 76.6 12.1 66 - 96 3 66.7 6.0 76 - 96 4 65.7 7.4 72 - 96 AA-2 -- 0.61 138.8 0 - 5 M4 -- 15.4 37.4 3 - 29 AANaBr—2 -- 7.2 70.5 1 - 22 AANaBr-4 - 77.6 13.0 36 - 92 corvoiv§ 2 579.4 16.7 424.5 - 713.0 3 488.2 13.7 361.2 - 570.6 4 455.2 10.9 379.3 - 529.2 1’ The range of values is for all the replications. :1: Values for the tests are expressed as % of seed germinated, except COND that is in 1.18 cm "9 “. § Only tests where the variable size was significant P s 0.05 in the ANOVA. 41 Table 11. Mean, coefficient of variance and range of seed treatment test results, Exp. 3 (Seed Enhancement). 1996 1999 Lab Tests Mean CV RangeT Mean CV Range % germination of seed tested PT-5 CBIPI'II 66.0 6.2 66.0 - 94.0 67.6 4.4 64.0 - 3.0 PAT 96.6 3.6 96.0 -100.0 64.0 7.5 76.0 - 69.0 TACH 61.0 13.6 56.0 - 66.0 79.3 4.2 75.0 - 63.0 PAT+TACH 63.6 21.6 76.0 - 96.0 77.5 3.9 73.0 - 79.0 Plain 96.0 4.6 96.0 - 100.0 95.5 1.6 94.0 - 96.0 PT—10 COIpI'iI 97.6 5.2 94.0 - 100.0 91.2 3.1 66.0 - 95.0 PAT 96.6 3.6 96.0 - 100.0 66.3 6.0 79.0 - 90.0 TACH 67.0 12.4 62.0 - 72.0 63.5 4.4 60.0 - 66.0 PAT‘I’TACH 69.6 22.4 76.0 - 96.0 60.5 4.6 76.0 - 64.0 Plain 96.6 3.6 96.0 - 100.0 96.3 1.3 95.0 - 96.0 CT-5 COIpl‘II 97.0 3.9 92.0 - 100.0 95.0 3.6 92.0 - 100.0 PAT 91.0 5.2 64.0 - 94.0 66.0 9.3 76.0 - 96.0 TACH 93.0 1.2 92.0 - 94.0 93.5 4.7 90.0 - 100.0 PAT'I'TACH 97.0 1.2 96.0 - 96.0 76.0 7.5 72.0 - 64.0 Plain 95.0 2.7 92.0 - 96.0 97.0 3.6 92.0 - 100.0 CT-‘Io COIpI‘II 99.0 2.0 96.0 - 100.0 95.0 3.6 92.0 - 100.0 PAT 92.0 5.9 64.0 - 96.0 66.5 9.3 76.0 - 96.0 TACH 94.0 1.7 92.0 - 96.0 95.0 4.0 92.0 - 100.0 PAT'I'TACH 97.5 1.0 96.0 - 96.0 79.5 6.6 74.0 - 64.0 Plain 95.5 2.0 94.0 - 96.0 97.5 3.9 92.0 - 100.0 1' The range of values is for all the replications. 42 The wide range between the pleated and cold test germination in Exp. 1 in 1998 showed the variation of seed quality. This is largely due to the impact of seed lots 18 and 10, which represented the lowest quality (Table 12). Although this may have been expected due to the age of these particular entries, the variation in seed quality for Exp. 1 in 1998 was also reflected by the larger coefficient of variation when compared with the other experiments (Table 8 - 11). Although viability tests usually do not detect vigor differences, they can be useful in determining some differences when such large variation in seed quality exists. Most seed lots in Exp. 1 in 1999 and the other two experiments were of acceptable market quality, defined by the sugar beet industry as 92.0% or higher in the pleated germination test. Most lots in these studies would have been acceptable except seed lots 85, 91 and 96, which did not meet the criteria in our pleated germination test (Table 13). Application of external stress to the seed holds promise as an additional means of measuring seed quality. In these experiments, three such tests were evaluated. Generally, there was a lower germination for the vigor tests than for the pleated test. Ten-day pleated germination averaged 92.5% across 20 entries in Exp. 1 in 1998, but none of the vigor tests averaged above 80.0% (Table 12). The sand emergence, accelerated aging over sodium bromide and cold test all had similar averages (77.1 - 79.6%). Accelerated aging over water had much lower values, with an average of 36.5%. 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F dxm 5 so. 82.. 8 as .2 3.82 .8. 82.233 .2 2...; 45 mNo cfia nda m.mm m.mm o.mm mda cda «2.0a 52n— m.2. «.2. «.8 3L «.5 «.3 «do «do Io82 «8 « 5. «F «8 « E. «F E. « E. «P E. « 8.58: 80H «30 flu... «mama Wok Boo muH 882m «com 32 8a— .82 «ca 32. 5:250:25 team. n .93 «5 5 8:25am: uaou o;— 05 .6“. 8.32 32 E2833 .2. «Eu... «s8 «.2 «2 «.8 36 «.8 «.8 «.2 «.8 «.3 «.8 «.3 «.3 «8.23 «.««« «.2. «5 «.« ««.« «.8 «.8 «.8 «.8 «.8 «.8 «.8 «.8 « «h «.«3 «.3. ««.« «.2 ««.« «.8 «.8 «.2. «.«v «.3 «.3 «.8 «.8 « «B «8.8 «.8 «N. «.« ««.« «.8 «.«v «.8 «.8 «.~« «. 3 «.8 «.8 N z. E«« «.8 «No «.2 «3 «.8 «.2. «.8 «.3. «.8 «.8 «.8 «.8 w «« «.««« «.8 «.2 «.2 «~.« «.8 «.2. «.8 «.8 «. 3 «. 3 «.3 «.~« « 8 «.«8 «.8 «3 «.8 «~.« «.8 «.8 «.8 «.3 «. 3 «.8 «.8 «.3 N 8 «.«8 «.8 ««.« «.2 «Z «.8 «.R «.3. «.8 «.8 «.8 «.8 «.8 v «« ~.««« «.8 «.«w «.2 «~.« «.8 «.2. «.8 «.B «.8 «.8 «.8 «.8 « «« «. .8 «.I ««.« «.8 ««.. «.2. «.8 «.8 «.8 «.8 «.8 «.~« «.8 a «« 375% 382 38 «0 «2555.3 8 1.3: E. « 8.. N E. « >8 N E. «« >8 « >8 « >8 « E. «. >8 « >8 «. >8 « 8% «Em ||I|.«««««o alaz «lg fill”; «:3 IE.» «.5222 IE» «.8 lack «28E j < «22 .83. «9: «.«o Acfim team. N dxm :_ 80. can» 2:: c5 .8 8.33.. 33 389.035.. .3. «Ba... 46 useful because of excessive mold development on some entries during incubation at 410°C. Similar results were found in the rest of the experiments. However, cold test results across seed lots in Exp. 1 (1999), 2 and 3 (1998 - 1999) were more than 100% higher than that of Exp. 1 in 1998 (Table 12 - 15). These higher results may have been due to temperature fluctuations (lower than 9.0°C) in the cold room and lack of proper maintenance of the soil moisture. Both factors have a direct effect on soilborne plant pathogens, which is thought to be the primary factor influencing the cold test germination (Woltz, et. al. 1998). This observation is also supported by the lower mean germination in the high moisture cold test for the same experiment (Table 13 and 14). The conductivity test produced the lowest average conductance values in Exp. 1 in 1998 (480.1 uS cm‘1 9“, Table 12). This was unexpected because Exp. 1 had the two lowest quality seed lots (entries 10 and 18). Low vigor seeds generally possess poor membrane structure and leaky cells, resulting in greater loss of electrolytes such as amino acids, inorganic ions and organic acids from seeds. These electrolytes increase conductivity in the soak water; therefore, a low vigor seed lot should posses the highest conductivity. However, this high conductance typically produced by low vigor seed lots was not observed (Table 12). Although the conductivity test on sugar beets has not been a good indicator of seed quality in previous investigations (Longden and Johnson, 1974 and Kraak et al., 1984), a possible explanation for poor quality seed lots 47 producing a low conductance might have been due to a masking effect of seed size on conductance. ln conductivity measurements of the soak water in which a bulk sample (75 seeds) had been steeped, seed size had a direct influence on the conductance. To illustrate the point, the size of this entry (# 18) was four (Table 1), the second largest of the four sugar beet sizes. Large seeds have a smaller surface area per unit weight, resulting in a lower diffusion rate than from small seed (Tao, 1978 and Bekendam, et al 1987). This observation was also confirmed in Exp. 2, in which smaller seed within the same variety had the highest conductivity of the three varieties tested (Figure 1). Otherwise there is large inconsistency in both conductivity and germination test results. However, another possibility for these results was the potential influence of seed treatment in the conductance of the water. Following the rationale explained above, seed from smaller size posses the largest amount of seed treatment per unit weight, thus perhaps influencing conductance. This emphasizes the need for standardization of vigor test procedures. 8. Simple Coefficients of Determination Simple coefficients of determination were used to establish the relationship between field emergence and laboratory test results. Significant coefficients of determination of r2 in excess of 0.500 occurred among results in Exp.1 and 2 (Tables 16, 17 and 18). A relationship of r2 = 0.787 occurred between the 5- and 10-d germination periods for the sand emergence, and the 48 2- and 4-d counts of the accelerating aging test over water and NaBr in Exp. 1 in 1998 (Table 16). However, there was a better relationship within the 5- and 10-d counts for the pleated test (r2 = 0.890) and a larger coefficient of determination between 5- and 10-d counts of the cold test (r2 = 0.990). Similar results were found in 1999, where relationships between the pleated germination and cold test were r2 = 0.980 and 0.966, respectively (Table 17). However, the high moisture old test had a 3- and 6—d coefficient of determination of just r2 = 0.691. In Exp. 2 the relationships between pleated germination and cold test results were also high (r2 = 0.853 and r2 = 0.875). Smaller coefficients (r2 < 0.780) occurred Conductivity Test 700 a Lsom=533 600 - - Size 2 .5‘ Size 3 -:-°’ 500 .. - Size 4 E O ‘3 v 400 - .2‘ .E ‘9 300 - 'O C O 0 200 . 100 — o _ ACH648 ACH503 ACH555 Variety Figure 1. The effect of seed size on conductance for the three varieties tested on Exp. 2. 49 .««.«w« «5 8 38885 . «««.« ono «:3 «8.? «1825 «83 .83 «8.. ~..m«z<< «83 6«.« .83 «««.« v.<< «33 2.3 S 3 .««3 «8., ~.<< «N3 .23 .83 .33 .83 «««.« «Em B 3 .283 .53 .83 .«Rd .83 «8. s «.._.w 83 .«o«.« .«-.« «33 33 .~««.« .83 83 «Eb «« 3 .«~«.« .83 F F 3 «83 .«83 .«««.« .«««.« «8. P «.5 .83 .«23 .83 .23 «83 :83 .83 .83 .«~«.« «8.? «Ed .183 .33 .~«~.« .8m.« 83 .53 .33 .83 .-«.« .«8.« «««.« «.E 0200 Tom—«25‘ N¢mwz<< Y<< ~.<< o 7.5 8.5 c 7.5 mare o :0 our". 28:. «3 .82 65:25 boom. «.96 «oh 8.32 «no. 329.com. 9.9.5 «0 5.355528 no 3:23:30 295m .3 038... 50 .838 «5 8 88588 . «8.. ono «««3 «8. . «.215 «««3 . .83 «8. . «-215 83 .53 8.3 «8.. «T5 «83 .83 .« .3 .833 «8. . «-5 «.«3 .33 «83 .83 8.3 «8.. «TE .36 .hNNd chad «w the «mend .oood oooé mnrn. 0200 «.215 «42:5 « ..5 «.5 « Fr... «.5 «.8. «3 .omaw 26:25 poem. . .oxm .5. 8.32 «no. 38232 9.088 N. cote-«3:83 no 8.520503 29:5 .2. snub 51 .838 «5 a «82.88 . 8«.. ono «83 8«.. 1825. ««3 .83 8«.. ~.«««z<< «.3 .~««.« .83 8«.. e-<< 8«.« 8«.« «.«3 «83 8«.. -<< «««3 .83 .83 ~83 3«.« «8.. «.-5 «~«.« .83 ...«.« «e3 .83 .«83 8«.. «.5 ~83 «.3 «~«.« «««3 8«.« 8.3 «-.« «8.. «.215 «83 «83 «««3 «83 «83 «.«3 «~«.« .83 8«.. «-215 .83 8.3 «.3 ««3 8.3 «««3 ~«..« 8.3 «83 «8.. «.-5 ~.~.« «~..« 83 8.3 .«~.« .83 83 «««3 .83 .«83 8«.. «.5 «.83 .83 «83 «83 8.3 «v3 «.3 «.3 ~83 .«3 8.3 8«.. «En «««3 «««3 83 8.3 «~..« «««3 8.3 «23 «83 «83 ~83 .«83 8«.. «.5 «200 182.2 -.««z<< «.5. -<< «.-5 «-5 «215 «215 «..5 «.5 «YE «-E «.8. 8.. .Aoufi «seem. a dxm ._o. 8.52 58 3222.2 9.25 N. 5.85.532. .o 8:20:53 «3E5 .3. «Ba... 52 among the other test results (Table 18), however, coefficients for the high moisture cold test and accelerated aging test over water were not significant. These data suggest that a 5-d count may be sufficient for the pleated germination and cold tests, but the longer period is needed for the other tests. There was not a close coefficient of determination among results of the various tests for the two experiments (r2 < 0.830, Table 16 - 19). However, the highest coefficient was between the pleated germination and cold test (r2 = 0.825) in Exp. 1 in 1998. A similar coefficient (r2 = 0.804) occurred between results of the pleated germination and accelerated aging over NaBr for the same experiment. Also, a relationship of r2 5 0.737 occurred between results of the sand test and the pleated test. In Exp. 1 in 1999 the coefficient of determination between the pleated germination and cold test results was lower than expected (r2 = 0.750), but was the highest among tests for that year (Table 17). Coefficients between the pleated germination and cold test results in Exp. 2 were not significantly different. The coefficient of determination between sand test and accelerated aging results over sodium bromide was of 0.780 for the same experiment. Results of Exp. 1 in both years support the use of the cold test as an indicator of viability, confirming observations of Akeson and Widner (1980) and Lovato and Cagalli (1992). Conductivity test results were poorly correlated with other test results in all experiments (r2 5 0.254). Sugar beet seeds consist of thick outer pericarp layers that disable the easy flow of the leakage of organic substances from the endosperm to the epidermis. The lack of significant coefficients of determination 53 between the conductivity test and other test results confirmed the research of Kraak, et al. (1984) and Bekendam, et al (1987). ll. Relationship Between Laboratory Test and Field Emergence A. §imgle Coefficients of Determination Simple linear coefficients of determination were computed among all laboratory results and field emergence for Exp. 1 and 2, but not for Exp. 3 because of inadequate data points collected. Many significant coefficients of determination greater than 0.500 occurred in Exp. 1 in 1998 (Table 19), but only a few for the same experiment in 1999 and Exp. 2 (Table 20, 21 and 22). This is consistent with observations from studies by Burris (1976) and Durrant et al. (1984). They found when seed lots with poor viability were included, coefficients of determination between field emergence and laboratory results were higher than when only seed of acceptable market quality was used. The 5-d cold test had the highest coefficient of determination (r2 = 0.917) for the final count at the Metea location in Exp. 1, 1998 (Table 19). In all three locations the cold test and pleated germination test had the higher coefficients. In contrast, the conductivity test and the accelerated aging test over water had lower coefficients (r2 s 0.467). The highest significant coefficient with field emergence of r2 = 0.588 occurred for the 10-d pleated test in the same experiment in 1999 (Table 20). 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J00 00.02 0200 3.032 ~..0«z .15. ~.<< 3....0 00.0 0.2.0.0 3.21.5 3....0 0.00 3...... 0-0.0 .330 00080.. 0.00... 020.000.. .333. 03.0 380. ~ .90. .0. 30003.3 .o «0... «0. .3 080300. 30 000090.00 0.0.. .x. 000 3.000. .00. E30300. 0003.00 N. 003058.300 .0 0.00.0500“. 0.0.0.0 .NN 0.00... 58 test produced the second best coefficient for this experiment. The high moisture cold test performed no better than the standard cold test, for which the highest coefficient (r2 = 0.394) occurred at the Metea location. The conductivity test did not produce significant coefficients with field emergence at any of the three locations and no significant coefficients for any test at the Capac location. Coefficients of determination at all three locations for Exp. 2 in 1998 were low and not significant (Table 21), perhaps due to the small sample size (n=9), smaller vigor differences and generally higher quality seed than that used in Exp. 1 in 1998. Although not significant, the cold test results had the highest coefficients with field emergence at all locations for Exp. 2 in 1998. Few significant coefficients occurred for Exp. 2 in 1999 (Table 22). However, there was a better coefficient between the 10—d cold test and field emergence at the early sowing compared to the late sowing (r2 = 0.857 vs. r2 = 0.654) for the same number of days after planting. Surprisingly, the conductivity test had slightly lower significant coefficients of determination with field emergence than the cold test for the early planting, however, at the late planting, none of the conductivity coefficients were significant. These results could be due to the favorable soil conditions for the early planting. Comparisons from all experiments showed that the cold test had the highest or second highest coefficient of determination with field emergence. Since the cold test measures emergence under artificially induced cold soil conditions it would be expected to correlate well with performance under field stress conditions, especially at the early planting of Exp. 2 in 1999 (Akeson and 59 Widner, 1980; Kraak et al., 1984). The better soil environment simulates the conditions used to demonstrate the vigor response in the laboratory, resulting in better coefficients between cold test vigor and field emergence. While coefficients of determination between pleated germination test results and field performance were highly significant in Exp. 1 in 1998, they were usually lower than those for all the experiments. These results agree with those of several other authors who have concluded that the standard germination test is reliable for predicting plant establishment of sugar beets in the field (Kraak et al., 1984; Durrant, Brown and Bould, 1985). The coefficients of determination between field emergence and sand test results were the third highest for Exp.1 in 1998 (Table 19), however, such coefficients were not achieved in any subsequent year or experiment. This is contrary to results obtained by Akeson and Widner (1980) in which sand test results for sugar beets were highly correlated with field emergence (r2 = 0.792 - r2 = 0.960). Aging, which is considered to be a major cause of reduced vigor in seeds (Perry, 1972), also failed to result in high correlation between laboratory tests and field emergence (Durrant et al. 1984; Kraak, and Vos, 1987). However, the physiological changes during the accelerated aging test may be different from those produced by normal aging processes. The low correlation with field emergence is in striking contrast with results cited earlier for large-seeded crops such as corn and soybean in which the accelerated aging test over water is an important seed vigor test. However, its value for small-seeded crops has been 60 limited because moisture uptake is too rapid, resulting in rapid seed deterioration for some species. Therefore, the accelerated aging over NaBr which only provided a relative humidity of 55.0% vs. ~ 100.0% over water showed significant coefficients of determination only in Exp. 1 in 1999. Measurement of the exudation of inorganic and organic electrolytes into water provides a rapid method for testing viability (Takayanagi and Murakami, 1968), however, for small-seed crops this measurement may not be useful (Longden, and Johnson, 1974; Kraak, and Vos, 1987). With the exception of the early planting in Exp. 2 in 1999, the conductivity test was poorly correlated with field emergence. Although this test is very convenient and can be completed in one day, its use in predicting field establishment does not merit further attention. No single laboratory test consistently had the highest simple linear coefficient of determination with field emergence for all stand counts over all locations. This is consistent with the opinion of many scientists that a single laboratory test simply cannot correlate well with field emergence over the entire range of possible planting conditions. Although these data confirm this hypothesis, they also show correlations between field emergence and different laboratory test results. 8. §tepwise Multiple Regression Analysis Laboratory and field emergence results were analyzed using a multiple stepwise regression technique. Results in Exp. 1 in 1998 (Table 23) show very good multiple coefficients of determination (R2) between 0.814 and 0.879. 61 ..038 .330 .33. 3.30 35.0.3.2 03.: "0.200 ..038 .333 .33. 3.30 35.3.3.2 03.... "32:0. .05. 0.3.0 0.... .0 .003.._00.0 .00 n0: 00:33 30.0 + 0.0 + 0.3 33.3.2 .303 3.2...0 + 0.0 33330 ..03 02:0 + 0.3 .3332»... 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"0.210 ..33. 0.2.2.3030 "0200 ..0000 0.0 .002 ..0>O 00.0... 00.0.0.000< u§m0z<< ..0000 0.0 .00. 0000 "0.0. 000.0 0200 + 0210 + 00.0 + 0.....n. 00000.05. 000.0 .0 .....0 00.02 000.0 0200 + «50202. + 00.0 >0000.0.2 mm .00_0000> .0000 000. glad-a4 .300 3330. u .90. .333. .0. 02.000. >0 00000000. 00 602.0000 000... .0. 02.000.00.00 .0 0.0220000 0.00.0.0 0... 000 .00200000 00.300 =0 .0 00000 00009050 0.0.. 3.. 0.0000> .00000000 0... 000 0.00. >.0.0..000. .0 02.0000 02000.00. 200.00. 02300.0 0 0. 30.000. 000000.000 >_.000...00.0 003000> .000000000. .0" 0.00 .. 63 .65. $04.“ 9: am Emoscgm 6c um: new _. Pd $202 man 56 .395sz 2336 9552a 2a.. 225d 828E 23m 0250 mcvomd «222 mam Nd 332$: m: qud >a=a£m=2 .Nlm. cozwoo ‘ mlm Ill—.333 mawp mmufl .35 .38. N dxm ..8 3592:» 20: s. 95052.. $3.352, Eon—.335 2: an :58 v.2. «ac... Eco uca :53 v.2. “no... 3.35 9:22. acozuaao 5.3952 ..8 Aux. scams—E23 no 353503 23:22 .3 win... .65. $06 05 um “£85ch 6: um: Sound 8ng Emma... 59565. «.586 8.22 283. «Ems. mconmd 332$: maimed 332$: mlm lllcozaoo; mm [5:83 aw _. ma _. 3:26 339 v dxm ..8 35938 Eat ax. 95059:. 333.? 23:33:. 05 no :58 v.2. «no... 200 uca :53 6.2. «no... $33.1 9.32. 2.03250 5.39.62 ..8 AN”: cows—._Eouou “—0 3:30:33 2.5.3.2 SN 03“... The 5-d cold test was the significant variable in two of the three locations in Exp. 1. However, the 10-d pleated test alone accounted for 87.9% of the total variability for the Kilmanagh location. The high moisture cold test appeared in three regression equations for Exp. 1 in 1999 (Table 24), with R2 values ranging from 0.211 (not significant at P5005) for the Capac location to 0.611 (significant at P5005) for Misteguay. Although the high moisture cold test did not by itself have a high simple linear coefficient of determination with field emergence, along with the 5-d pleated germination or 5—d cold test, it made a significant contribution to the multiple coefficients of determination equations, explaining about 11.0% of the variation for this experiment. The highest and the lowest R2 values of 0.980 and 0.486 occurred for the Kilmanagh and Metea locations, respectively, for Exp. 2 in 1998 (Table 25). Again, the cold test appeared in the multiple coefficient of determination equation for two of the three locations, and the conductivity test made a significant contribution in two of the three equations. However, the conductivity test was not by itself significantly correlated with field emergence at any location. The coefficient of multiple determination for Exp. 2 in 1999 (Table 26) was lower than that of the same location for 1998 (Misteguay). However, the 2-d accelerated aging over sodium bromide test accounted for more than twice the variability in 1999 than in 1998 for the same experiment. Furthermore, the 10-d cold test appeared as an independent variable for two of the three locations. Early planting had a higher coefficient of determination than late planting at 0.873 65 and 0.645, respectively, for the Capac location in the same experiment. Cooler soil and better soil conditions were factors that contributed to a higher R2 value, confirming observations by Kraak, et al. (1984) and Payne and Williams (1990). High soil temperature and moisture during seedling development favor growth of Aphanomyces cochlioides and thus the incidence of infection. This is specially true for late plantings with warmer temperatures at which may lead to partial or complete stand establishment failure in some years. Damping-off caused by Pythium spp. is less frequent in the field, but may be under-reported because infected seedlings die before or soon after emergence. Since the cold and pleated germination tests appeared in most of the stepwise multiple coefficients of determination, equations with these two variables were computed for all locations for both experiments in both years. However, Table 27 and 28 show that the R2 values were not significant, and no better than those for the stepwise multiple regression equations when all other tests were included. The use of a combination of tests to predict field emergence of sugar beet has been suggested by other investigators (Longden, and Johnson 1974; Kraak, et al. 1984; Yaklich and Kulik 1979; Durrant, et al. 1984; Lovato and Cagalli 1992). Likewise, in soybeans, Yaklich (1979) used the best R2 values from all possible multiple regression equations to evaluate the usefulness of similar vigor tests. By using a number of laboratory tests to measure several different aspects of vigor, test combinations having high R2 values have been found that will predict field emergence results under similar seedbed conditions. However, vigor test results reflect the conditions of the individual test and may not explain all the processes and reactions occurring at the field level. III. Influence of seed size on germination and field emergence (Exp. 2) A. Laboratom Tests: In most comparisons, seed size was not significantly associated with pleated seed germination (Table 29). The cold test did not produce significant differences among seed sizes. Three-day high moisture cold test results on seed size two was significantly different than on those of size four for the variety ACH55. Two of the three varieties showed a significant difference in the sand test performance between seed sizes two and four. Few differences also occurred among seed sizes in the accelerated aging test, however, little consistency occurred among results of accelerated aging tests over water vs. sodium bromide. Significant differences in conductivity test results between the smallest and largest seed sizes (two and four) occurred for the three varieties tested. Surprisingly, the smallest seed size produced the highest conductance and vice versa, however, an explanation for the masking effect of seed size on the conductance of water was previously explained in section IA. B. Field Emergence: Contrary to findings by Lexander (1981) and Akeson (1981), seed size did not have a significant overall influence on field emergence in 1998 (Table 30). The 12-d Kilmanagh and Misteguay 23-d counts for the ACH503 variety were the 67 only comparisons that produced significant emergence differences between size two and four for the same year. In 1999 the early planting produced no significant differences in emergence due to seed size, which is consistent with 1998 findings (Table 31). However, in the late planting most of the comparisons produced significant differences in emergence due to seed size. Although no relative ranking was made, significant differences between seed size two and four occurred in almost all of the comparisons. Many growers believe that larger seeds have better emergence potential than smaller ones, however, my research did not support this belief. Although larger seeds had significantly higher emergence at the late planting in 1999, this "grower belief" can not be consistently confirmed because such late planting dates are not feasible. Akeson (1981) also reported no differences in field performance for seed size of 3.6 - 4.0-mm vs. 3.2 - 3.6-mm. Lodgen (1986) indicated that large seeds did not necessarily germinate better than small ones since large seeds could be a result of increased pericarp volume alone. IV. Influence of Seed Treatment on Field Emergence (Exp. 3) All seed treatments produced higher emergence than the standard Celpril treatment (film coating with Thiram) for all counts at the early planting (4/15) in 1998. However, the priming advanced treatment (PAT) resulted in earlier emergence than any other treatment. At the 11-d count, PAT-treated seed emerged 97.7%, more than the standard treatment with Celpril (Figure 2). Celpril treated seed always had the lowest emergence for this planting date. Although 68 ._o>m_ $o.m 9: am EEmEu 2.50588 2m 825. 226.56 55, 39...? 9:8 9: £53 838) w .3059: new 29.29: c_ beacon mm mum no.8 “woman. u v .umm__mEm u N + 8.8» 8.2. a 3 8.8 88 8.8 8.8 8.8 8.8 8.8 8.8 8.8 8.8 w 884 8.:. a .8 8.2 86 8.8 8.8 8.8 38.8 8.8 8.8 8.8 8.8 n 888 8.8 a 3 8.8 88 8.2. 8.8 8.8 8.8 8.8 8. 3 8.8 8.8 N 882 3.88 8.8 a 3 8.: 88 8.8 38.2. 8.8 8.8 8.8 8.8 8.8 8.8 8 8.88 8.8 a 3: 8.2 8... 8.8 8.8 8.8 8.8 8. 3 8. 3 8.3 8.8 n 8.88 8.8 a 8.8 8.8 88 8.8 8.8 8.8 8.8 8. 3 8.8 8.8 8.8 N 88:2 8.8.. 58.8 a 3. 8.3 8.~ 8.8 8.? 8.: 8.8 8.8 8.8 8.8 38.8 v 888 8.8 a 3: 8.3 8.8 8.8 88 8.8 8.8 8.8 8.8 8.8 8.8 n 8. 8 8.: a 3. 588 8.. 8.8 8.8 8.8 8.8 8.8 8.8 8.8 H88 R 88.2 2-9.58: Bus 88 ..o 885.58 .x. a. . >8 8 8 u 8 4 8 N >aufiu m >En >8Emu m >5: 8 08 28> 08:8 .28) 8... 2.8 8» 838.2 8... 38 8* B385 8f :8 8313.235. 5 32.2, ecu on? com» 3 beacon—=5 mu gowns-Eon 6...—boom .mu 2%... 69 .65. 898 on. 6 E2326 23:85:96 2m 9.2.6. E2853 5.3 bot? 2.8 m... 55.3 mm:_m> H .9353 .28 260 ._. a 8.8 a v.8 a 8.8 a ..8 a h. 8 a 5.8 a «.8 a v.8 a 8.8 3. a 8.8 a .8... a Q: a 88 a 8.8 a 8.8 a :4 a N8 a no... 8 a 2:. a 5.8 a 8.8 a 8.8 a ..8 a 8.8 a a. 8 a 8.8 a 3» N 8813. a 12. a h. E a 58 a 8.8 a 8.8 a 8.8 a 4.8 a 0.8 a «.NN v a 34 a 8.: a v.3. a 8.8 a «.8 a a8 a 8.8 8 «.8 a 8.8 a a «.8 a 98 a a. 8 a 8.8 a 8.8 a 8.8 a we: a ~. 3 8 88 N 88.2 a v.8 a 8.8 a 0.8 a 8.8 a as... a n. E a .8 a 8.8 a 8.8 v a «.8 a ..8 a N8 a 98 a 8.8 a VS a 8.8 a 8.8 a m. 8 n a In a ..8 a 3.8 a F. 8 a 8.8 a 8.8 a 8.9. a 3.... ”a 8.8. ~ 88:9. 8.8... 88 ..o g. 8 8 «F 8 2 2 8 8 t. 8% 88> 838.84% 8.22 #8988 .33 E mazes... Btu «>8. one cos—woo. 50...; in.» too» .3 03:83:... on 35925 3.53m .on 033. 7O .mczcmE .22 £60 m .55. $06 9: am 523% $505ch 9m ago. €236 5? 32.9 mEmm or: £55, mm:_m> n .motom :8 $3365 on. E “.253 295 Emu mczcma 50m ._. a 5.3 a ad» a ode m NE. a man a 0.2.. a 0.8 a «.3 a oéN a 93 v a 93 no «as as o...» a 92. a v.8 a 98 a You a 98 a 93 a no? a a fine a ado a N! a m. z. a tam a «em a :N a «.NN a «.2 a 3: N 833 a v.2. a too a v.3 a ado n 98 a m.- a o. E a flow a v.2 a n. 2 e a ado a ads on 02. a fit. a 5.: a 0.8 a Now a Vow a fit. a N. 3 m a «do a 92. a h. S a two a 5.3 a h. E a n. E a n. R a «.8 a ..3 N «812 a tum an 9.3 a was a 92. a Ev a m. N a SN 5 o. R a 0.9 a v.3 v a 93 a 9Q. a QR a Qfl an 93. a new a 92 a 92 m 3. a 2: m a mg a m. B a 98 a 03 a «.8 a 2.. a 5.2 a 5.. a «.2 ”a 3 N 96:3 3.33 33 8 .x. 5 3." rm 3 o NV 5 on mm a: 3E 5953 h 53 9.35:. 23 3:3 Sign. ram .32. :_ 955... ha 2:: new bot—2, 65» .33 >3 3253:... ms 00:092..» uEEomm .3 035... 71 the relative ranking among the other treatments was not consistent, all the seed treatments induced similar emergence to that of PAT treated seed at the later counts. At the last count (44—d) the PAT and Plain Pelleted seed emerged 60.0%, which was approximately 10.0% higher than Celpril treated seed. However, none of the seed treatments were able to meet the goal of the so- called "crop success" of 70.0%. In the late planting (5/15) in 1998, overall trends in stand establishment were similar to those in the early planting, however, the stands for all seed treatments were significantly lower. Again, PAT treated seed emerged earlier than that of other treatments. Nineteen days after planting, 10.8% of seedlings from PAT treated seed had emerged, compared with only 2.6% of those from the Celpril treatment (Figure 2). However, the other three seed treatments induced similar emergence to that of PAT treated seed at later counts. Furthermore, the difference among treatments was not significant at the 38-d, 42-d and 45-d counts. Priming has been shown to increase the earliness and uniformity of sugar beet seedling emergence (Durrant et al. 1983, Longden et al. 1979, Osbum, and Schroth, 1988), resulting in a lower incidence of seedling loss due to damping-off pathogens such as Pythium ultimum Trow (Harman and Taylor, 1988; Osbum, and Schroth, 1988 and 1989; and Rush 1991 and 1992). Pythium spp. is a soilborne pathogen that can infect the seed very quickly after planting, inhibiting germination and resulting in poor stands from both pre-emergence and post- emergence damping-off. However, the pre-emergence phase is more common. 72 Lsoo,,,5=7.7 I 5% '— .1” E 100 73 ' 5 .s < .‘2 1- (L G | | S to v "3 .5! Q 0 ‘c'u' .1 .0 fl 8 a ., a, O adta’txdfifi. F .1 I co 2 . m Lg. I 6232123525132;2525:5553; h .2 C 0 C) $— 0 E LU 2 .9 LI. A In t 3; a .E on: C .‘P. (L >5 t N LIJ .0 o W I 4::;:;:;:;:;:;:;:;:;25;:;:;:;:;:;r;:;f$:1:1;i:i:1>‘¢-T;i:; D (96) 901.1961er 13191:! I T T T I I F I I | 0) co rs co .0 v n N ‘— 45 42 38 24 31 19 28 22 19 16 13 11 Days After Planting 1 998 In field emergence for Exp. 3 ' ing on f plant me 0 Influence of seed treatments and t Figure 2. Protection against Pythium ultimum has been attributed to escape, reduction in seed exudates and a decrease in indigenous bacteria on primed seed (Leach, 1947; Leach and Smith, 1945; Osburn and Schroth, 1989). Although seed priming can reduce loss to seedling infection by Pythium ultimum, seedling disease caused by Aphanomyces cochlioides is not affected (Rush, 1992). A. cochlioides is a warm-temperature pathogen which typically infects the hypocotyls of sugar beet seedlings after emergence and is dependent on almost saturated soil for zoospore movement and infection (Buchholtz, 1944a and 1944b, McKeen, 1949; Papavizas and Ayers, 1974). However, in these studies, Celpril coated seed was not as effective as PAT against soilborne pathogens, especially in the late planting. Thiram is thought to be more effective against seedborne pathogens (like Phoma betae) rather than soilborne pathogens (Durrant, et al., 1988, Payne, and Williams, 1990). However, there is a possibility that steeping seed in Thiram could exert some control on soilborne pathogens from either a fungicidal effect (Maude, 1983) or as a result of increased seedling vigor, reducing the period during which seedlings are susceptible to infection (Durrant, et al., 1988). However, earlier studies showed that when Thiram and hymexazol are present in a seed pellet, protection against Phoma betae, Phoma spp. and A. cochlioides might be achieved, depending on the relative amount of soilborne pathogens present (Payne, and Williams, 1990). Although similar stand establishment levels occurred at both planting dates, the overall mean emergence was much lower at the late planting. For example, plain pelleted seed had the highest emergence at 28.8% for the late 74 planting (31-d count) compared to 59.9% (28-d count) for the early planting. Colder temperatures during the first planting and warmer temperatures at the late planting, along with 36 mm of rain in the week before late planting and poorly drained soil conditions all contributed significantly to the lower stand counts for all seed treatments at the late sowing. A. cochlioides and Pythium spp. alone or in combination are frequently cited as significant causes of seedling loss in different countries (Dunning and Heijbroek, 1981, Papavizas and Ayres, 1974; Yanaguchi, 1977). However, Pythium spp. which attacks younger seedlings appears only briefly and do not cause major crop losses (Payne, and Williams, 1990). In contrast, the warm-temperature pathogen A. cochlioides, can cause detrimental effects by infecting the tap root and fibrous root system of the developing crop under high temperature and wet soil conditions (Papavizas and Ayres, 1974). In a survey of fungi causing seedling diseases conducted in Europe in the early 1980's, A. cochlioides and Pythium spp. were found to occur in 39.0% and 31.0%, respectively, of 341 sugar beet fields surveyed (Payne, et al., 1994). However, the frequency of A. cochlioides-infested soils varied widely in the different sugar beet growing areas. To mimic this variation in 1999 our research mnsisted of three sites with different indices of Aphanomyces spp.. A soil bioassay showed the index of 3, 28, and 94.0% for Sites 1, 2, and 3, respectively (Table 7). In Site 1 where the organism index was low, no significant differences were found between seed treatments for the first three emergence counts (Figure 3). However, at the last count (21-d), significant differences in 75 emergence occurred between Plain pelleted seed and the combination of primed advance treatment with the fungicide Tachigaren (PAT+TACH). The highest (78.8%) and the lowest (64.5%) emergence occurred for Plain pellet and PAT+TACH treated seed respectively, throughout the four counts. The overall emergence for all seed treatments on Site 1 was high. This is not surprising since no beets had been grown in this field during the past 25 years, resulting in minimal disease inoculum potential. However, in Site 2, sugar beets had been grown in a three-year rotation with other crops, therefore the organism index was medium and clear emergence differences and lower mean emergence occurred. At the 21—d count the highest field emergence levels of 63.5 and 62.5% occurred for the standard film coating treatment Celpril and the Plain pelleted, respectively (Figure 3). Contrary to the findings in Sites 1 and 3, the highest emergence was with PAT+TACH treated seed (38.5%). There is a possibility that coating with Thiram (the fungicide in the Celpril treated seed) could exert control on soilborne pathogens, either from a fungicidal effect or as a result of enhancing seed germination and reducing the period during which seedlings are susceptible to attack. However, when Celpril was compared in a high organism index environment like that of Site 3, the incidence of seedling mortality from infection by Aphanomyces spp. was as low as that for Plain pellet treated seed (Figure 3). At the 21 —d count 14.8% emergence occurred for both treatments, indicating that Thiram alone does not perform well under severe disease conditions. However, when combined with a treatment that will enhance germination with a fungicide (Tachigaren), like PAT+TACH treatment, a sugar beet stand can be tripled under 76 Emergence (%) Emergence (%) Emergence (%) Field Emergence for Experiment Three - 1999 100 LSDO_°5=14.0 9° ‘ Site One (Low Disease Index) so - MS. MS. MS. 70‘ ab Site Three (High Disease Index) ab flba 9 14 17 Days after planting - TACH PAT+TACH - Plain Figure 3. Effect of seed treatments on seedling emergence from soils infested with different level of Aphanomyces spp. 77 conditions with severe pathogen levels (41.0%). Thus, at the 9-d count all the treatments had a significantly higher emergence than those at Site 2 for the same count. However, the mean emergence of all seed treatments was significantly lower at 21-d in Site 3 compared with Site 2 for the same time. Higher incidence of Aphanomyces spp., wet soil, high temperatures and cut worm damage all contributed to the gradual stand establishment loss in the Site 3. 78 SUMMARY Comparisons of seed quality/vigor test and field emergence results were made in 1998 and 1999 in three different experiments. Experiment One utilized seed lots representing a wide range of seed quality, from different production years and lengths of storage. Seed lots used in Exp. 2 were of high quality and represented three varieties with three different seed sizes. Experiment Three consisted of a commercially grown seed lot enhanced with the following five seed treatments: Celpril (film coat of the fungicide Thiram); PAT (primed advance treatment); TACH (pelletized seed with the fungicide Tachigaren added); PAT+TACH (combines the primed advance treatment and Tachigaren) and Plain Pellet (Celpril treated seed covered in a pellet without further treatment). Laboratory tests used to evaluate seed quality and vigor included the standard pleated germination test counted at 5 and 10 d, the 5- and 10—d cold test, the 3- and 6-d high moisture cold test, the 2- and 4-d standard accelerated aging test, the 2-and 4-d accelerated aging test incubated over NaBr, the 5- and 10-d sand test and the bulk conductivity test. Field emergence data were collected at Saginaw, Ingham and Huron counties in 1998 and in Saginaw and Ingham counties in 1999. I. Laboratory Tests Significant correlations between the pleated germination and cold test results occurred in Exp. 1 during both years. This confirmed the potential of 79 these tests to differentiate within a wide range of seed quality as that used in Exp. 1. Furthermore, the high correlations between the 5-d and 10-d counts for the pleated germination and cold tests suggest that the 5-d germination count may be sufficient. Although significant correlation also occurred between results of the sand and accelerating aging tests over sodium bromide for Exp.1 in 1998 and Exp. 2, the correlations were not as high as those found between the cold and pleated germination test. Poor correlations were also found for the high moisture cold test, the standard accelerated aging test and the conductivity test for both experiments. ll. Relationship Between Laboratory Test and Field Emergence Results of pleated germination and cold tests were significantly correlated with field emergence for all three experiments when using the simple coefficients of determination. Cold test results were better correlated with field emergence under lower soil temperature conditions like those at the early planting in Exp. 2 in 1999. However, the cold test also performed well as soil temperatures increased. On the other hand, the high moisture cold test performed no better than the standard cold test. Correlations between the sand test results and field emergence were the third highest for Exp.1 in 1998. However, such correlations were not achieved during any subsequent year or experiment. Results of accelerated aging tests over water and sodium bromide were not significantly correlated with field emergence. With the exception of the early planting for Exp. 80 2 in 1999, conductivity test results were also poorly correlated with field emergence. Multiple stepwise coefficients of determination were calculated for each location in Exp.1 and 2, with each equation consisting of a different set of independent variables (laboratory tests). For most equations, the coefficients of the variables on field emergence accounted for over 49.0% of the variability. The cold and pleated germination tests appeared in most of these equations. However, when these two variables were regressed on field emergence for all locations on both experiments, the resulting R2 values were usually lower and did not significantly contribute to the equations. lll. Influence of Seed Size on Germination and Field Emergence In the majority of the comparisons, seed size was not significantly associated with the laboratory test results. However, a masking effect of seed size was observed in the conductivity test. Overall, seed size in 1998 and early planting in 1999 did not significantly influence field emergence. However, at the late planting in 1999, most of the comparisons produced significant differences in percent stand establishment between seed size two and four. Although, these differences were significant, no relative ranking among seed sizes was made because of inconsistencies in performance of different seed sizes among varieties. 81 IV. Influence of §eed Treatments on Field Emergence Two planting dates were selected in 1998 (4/15 and 5/15) to evaluate the influence of planting date on the emergence of the treated seed. In the early planting, all seed treatments produced higher emergence than the standard Celpril treatment. However, the priming advanced treatment (PAT) induced more rapid emergence than any of the other treatments. Celpril treated seed always produced the lowest emergence throughout all the counts. Again, in the late planting, seedlings from PAT treated seed emerged earlier than those from other treatments. However, the other three seed treatments (Celpril, TACH, PAT + TACH, Plain) induced similar emergence to that of PAT treated seed at later counts. On the other hand, Celpril coated seed was not as effective as PAT in controlling soilborne pathogens, especially at the late planting. Although a similar stand establishment trend occurred at both planting dates, the overall mean emergence was significantly much lower at the late planting date. In 1999 all treatments were planted at the same time, however, three sites with varying Aphanomyces spp. indices were chosen (low, medium, high). In Site 1 the seedling emergence was not significantly different among the seed treatments for the first three counts. At the last count, significant differences occurred between Plain pelleted seed and the PAT + TACH. The overall emergence for all seed treatments on Site 1 was high. At Site 2, where the organism index was medium, the overall emergence was lower than that at Site 1 for all five seed treatments. Contrary to the findings in Site 1, the lowest emergence occurred for the PAT + TACH treated seed. At the last count, the 82 highest field emergences occurred for both Celpril and the Plain pelleted seed. However, when Celpril was compared in a high organism pressure environment like that on Site 3, the incidence of seedling survival was as low as that of the Plain pelleted seed, indicating that Thiram alone (fungicide contained in Celpril) does not perform well under severe disease conditions. However, when combined with a treatment that will speed up the germination with a fungicide like PAT + TACH, the resulting stand can be significantly improved under such severe disease conditions. This confirms the effect of TACH (Tachigaren) in controlling Aphanomyces spp. 83 CONCLUSIONS The following conclusions can be drawn from these studies: 1. No single laboratory test can predict field emergence under all environments, because of the wide range of favorable and unfavorable soil and temperature conditions. 2. Variation in emergence under different planting conditions is likely due to varying environmental conditions, including biotic factors, rather than to intrinsic differences in seed quality/vigor. Even aging treatments, which are intended to test physiological vigor, failed to result in higher coefficients of determination between laboratory test results and field emergence. 3. The use of the pleated germination test plus the cold germination test should give the best indication of potential field emergence under most field conditions found in Michigan. 4. A 5—d germination count may be sufficient for the pleated germination and cold test. 5. No consistent association was found between seed size, germination and field emergence. 6. Celpril treated seed performed as well as other seed treatments/enhancements under low and medium disease environments at the late planting date. 7. PAT (Priming Advance Treatment) resulted in a lower incidence of soilborne diseases by reducing the period during which seedlings are susceptible to the pathogens. 8. PAT + TACH could be used to provide control over soilborne pathogens when field infestation is high. Overall, these studies showed conclusively that there are no intrinsic problems with seed quality/vigor in the sugar beet industry in Michigan. The study also showed that emergence problems in sugar beet seed are unlikely to be avoided by the application of vigor tests. Therefore, more attention should be given to studying soil and environmental factors which limit germination and stand establishment. Rather than seed quality, the problem appears to be abiotic and biotic factors in the soil that affect germination and stand establishment, even with the use of high quality seed. Agronomic practices such as crop rotation should be continued to help minimize seedling loss from pathogens. Finally, seed treatment strategies should be continued to help avoid seedling loss during and immediately following germination. This, along with appropriate agronomic practices and the continued use of high quality seed should help keep the need for replanting to a minimum. 85 APPENDIX 86 Table A1. Table A2. Analysis of variance for the pleated germination, cold and sand test results for Exp. 1 (Seed Quality), 1998 as Influenced by variety, time of count and replication. Pleated Test Cold Teg Sang ng M gr F-value Pr>F F-yglue Pr>F E-value Pr>F Variety 19 76.08 <.0001' 1013.40 <.0001* 169.41 <.0001* Time 1 305.93 <.0001" 56.85 <.0048* 1846.27 <.0001" Rep 3 0.36 0.7791 6.38 0.0811 31.64 0.0090‘ Var‘Time 19 54.76 <.0001* 4.19 <.0001" 7.53 <.0001* * Significant at the 0.05 probability level Analysis of variance for the accelerated aging test results for Exp. 1 (Seed Quality), 1998 as influenced by variety, time of count and replication. Accelerated Aging m: Hal—Br m d_f m BEE m Pr>F Variety 19 86.22 <.0001* 9.94 <.0001* Time 1 13053.1 00056" 2292.8 0.0043- Rep 3 10.56 0.1900 51.18 0.0884 Var‘Time 19 7.90 <.0001* 2.00 0.0699 * Significant at the 0.05 probability level 87 Table A3. Slicing procedure for the interaction effect between variety and time of count for the pleated germination test In Exp. 1 (Seed Quality), 1998. Sliced by Time ime g1 F-Valug £321: 10 days 19 33.09 <.0001" 5 days 19 112.96 <.0001" Sliced by Varlety 198$! 91 E13812 ERE 1 1 2.89 0.0942 2 1 0.41 0.5261 3 1 1.63 0.2071 4 1 0.41 0.5261 5 1 7.64 0.0076" 6 1 10.17 0.0023" 9 1 0.05 0.8324 10 1 13.06 0.0006" 11 1 0.05 0.8324 14 1 5.47 0.0227" 15 1 6.51 0.0133" 16 1 2.89 0.0942 17 1 0.41 0.5261 18 1 1200.41 <.0001" 20 1 35.42 <.0001" 21 1 6.51 0.0133" 52 1 19.92 <.0001" 54 1 16.31 00002" 56 1 14.64 0.0003" 57 1 1.63 0.2071 * Significant at the 0.05 probability level 88 Table A4. Slicing procedure for the interaction effect between variety and time of count for the cold test in Exp. 1 (Seed Quality), 1998. Sliced by Time 11m if - al P_r>.E 10 days 19 469.41 <.0001" 5 days 19 548.19 <.0001" Sliced by Variety 1892!! 9.! ._¥_L£F- a U BEE 1 1 14.18 00004" 2 1 2.27 0.1375 3 1 0.14 0.7079 4 1 0.00 1.0000 5 1 2.27 0.1375 6 1 2.27 0.1375 9 1 0.14 0.7079 10 1 6.95 0.0108" 11 1 0.14 0.7079 14 1 3.55 0.0648 15 1 5.11 0.0277" 16 1 1.28 0.2633 17 1 0.57 0.4544 18 1 56.74 <.0001" 20 1 23.97 <.0001" 21 1 0.57 0.4544 52 1 31.91 <.0001" 54 1 9.08 0.0039" 56 1 0.14 0.7079 57 1 0.57 0.4544 * Significant at the 0.05 probability level 89 Table A5. Slicing procedure for the Interaction effect between variety and time of count for the accelerated aging test in Exp. 1 (Seed Quality), 1998. Sliced by Time Iim_e d_f F-Value fl>_F 2 days 19 40.84 <.0001" 4 days 19 53.28 <.0001" Sliced by Variety Man's-mt m E___1;_-Val e M 1 1 37.06 <.0001" 2 1 1.42 0.2483 3 1 85.81 <.0001" 4 1 123.57 <.0001" 5 1 60.96 <.0001" 6 1 88.28 <.0001" 9 1 54.92 <.0001" 10 1 8.48 0.0090" 11 1 58.91 <.0001" 14 1 76.29 <.0001" 15 1 76.29 <.0001" 16 1 45.55 <.0001" 17 1 52.98 <.0001" 18 1 0.16 0.6958 20 1 12.77 0.0020" 21 1 30.89 <.0001" 52 1 29.44 <.0001" 54 1 14.73 0.0011" 56 1 16.83 0.0006" 57 1 13.73 0.0015" * Significant at the 0.05 probability level 90 Table A6. Slicing procedure for the interaction effect between variety and time of count for the sand test in Exp. 1 (Seed Quality), 1 998. Sliced by Time M9. g E-yalue Egli 10 days 19 62.38 <.0001" 5 days 19 114.56 <.0001" Sliced by Variety riet gt F-yglue Egfi 1 1 27.65 <.0001" 2 1 3.79 0.0564 3 1 6.41 0.0141" 4 1 9.71 0.0029" 5 1 38.84 <.0001" 6 1 18.36 <.0001" 9 1 0.34 0.5614 10 1 12.29 0.0009" 11 1 8.53 0.0050" 14 1 15.17 0.0003" 15 1 43.84 <.0001" 16 1 3.07 0.0850 17 1 20.06 <.0001" 18 1 155.35 <.0001" 20 1 23.70 <.0001" 21 1 43.84 <.0001" 52 1 54.77 <.0001" 54 1 83.78 <.0001" 56 1 41.30 <.0001" 57 1 46.46 <.0001" " Significant at the 0.05 probability level 91 Table A7. Analysis of variance for the pleated germination, cold, high moisture cold and conductivity test results for Exp. 1 (Seed Quality), 1999 as influenced by variety, time of count and replication. Cold High Coggggtiyity Pleated Test Cold Test Moisture Teg lest _S_0_ULC_§ 0: film _E_r_>_E F-value Pr>F F-value Pr>F F-yalge Pr>F Variety 19 11.31 <.0001* 5.65 0.000* 2.64 <0.202* 42.02 <.0001* Time 1 42.34 <.0001* 5.26 0.0818 59.99 <.0001* NIA NIA Rep 3 2.16 0.1032 0.93 0.9840 2.90 0.1047 0.23 0.8718 Var"Time 19 1.31 0.2168 0.29 0.1990 0.56 0.7692 NIA NIA * Significant at the 0.05 probability level NIA = Effect Non-applicable for the test Table A8. Analysis of variance for the pleated germination, cold, high moisture cold and sand test results for Exp. 2 (Seed Size) as influenced by variety, seed size, time of count and replication. Cold High Sand Pleated Test Cold Test Moisture Test Test Source 91 F-yglue P1>E F-value Pr>F F-valug Pr>F E-valgg Pr>F Variety 2 6.48 0.0317* 4.97 0.0534 0.97 0.5080 12.27 00076" Size 2 0.50 0.6077 0.30 0.7459 1.50 0.2543 22.78 <.0001* Time 1 25.98 <.0001“ 3.17 0.0818 46.41 <.0001* 131.47 <.0001* Rep 3 0.78 0.5468 0.05 0.9840 0.51 0.5488 0.17 0.9099 Var‘Size 4 2.94 0.0307* 1.57 0.1990 0.56 0.6937 1.80 0.1446 Val‘Time 2 0.36 0.6978 0.42 0.6619 1.28 0.3077 8.78 00006" " Significant at the 0.05 probability level 92 Table A9. Table A10. Analysis of variance for the pleated germination, cold and sand test results for Exp. 2 (Seed Size) as influenced by variety, seed size, time of count and replication. Water Nagr Conductivity lg Source df F-value Pr>F F-value Pr>F F-value P2P Variety 2 23.05 <.0001" 18.83 <.0001" 53.51 <.0001" 2 Size 2.01 0.1451 5.22 0.0089' 38.55 <.0001' Time 1 452.59 0.0002* 24573.8 <.0001' NIA N/A Rep 3 2.41 0.2449 13.91 0.0289" 0.87 0.4744 VaI‘Size 4 2.39 0.0642 2.40 0.0628 2.39 0.0892 Var"l’ime 2 19.59 <.0001" 4.23 0.0203“ NIA NIA " Significant at the 0.05 probability level NIA = Effect Non-applicable for the test Slicing procedure for the interaction effect between variety and seed size for the pleated germination test in Exp. 2 (Seed Size). Sliced by Size S129 g: F-Value P_r>_E 2 2 6.21 0.0041" 3 2 3.47 0.0397* 4 2 5.07 0.0103" Sliced by Variety m 91 E-yalue 32E ACH503 2 1.04 0.3604 ACH555 2 0.25 0.7790 ACH648 2 5.08 00103" " Significant at the 0.05 probability level 93 Table A1 1 . Table A1 2. Slicing procedure for the interaction effect between variety and germination time for the sand test in Exp. 2 (Seed Size). Sliced by Time lime 01 - Iue P_r>E 10 days 2 1.88 0.1641 5 days 2 19.96 <.0001" Sliced by Variety M31320: 9.1 F- In E_I>_F. ACH503 1 37.28 <.0001* ACH555 1 96.17 <.0001* ACH648 1 15.58 0.0003* * Significant at the 0.05 probability level Slicing procedure of the interaction effect between variety and aging time for the accelerated aging test In Exp. 2 (Seed Size). Sliced by Time 1er 9.! F- ue Eri 2 days 2 0.58 0.5626 4 days 2 42.06 <.0001* Sliced by Variety My 01 MM. M ACH503 1 260.45 <.0001* ACH555 1 62.60 <.0001* ACH648 1 204.85 <.0001" " Significant at the 0.05 probability level 94 Table A13. Slicing procedure of the interaction effect between variety and time of aging for the accelerated aging test over NaBr in Exp. 2 Table A14. (Seed Size). Sliced by Time Iim_e 9! 51/2016 212E 2 days 2 2.97 0.0610 4 days 2 20.09 <.0001" Sliced by Variety M! 9.! living BEE ACH503 1 1380.32 <.0001" ACH555 1 1040.48 <.0001" ACH648 1 1228.80 <.0001" * Significant at the 0.05 probability level Analysis of variance for pleated germination and cold test results for Exp. 3 (Seed Enhancement), 1998 as influenced by treatment, time of count and replication. Pleated Test M M d_f EM Er>_F fialu_e BEE Treatment 4 42.26 <.0001" 3.79 0.0204" Time 1 12.96 0.0026" 9.22 0.0083" Rep 3 0.99 0.4223 1 .24 0.3306 Treat'Time 4 1 .55 0.2341 0.45 0.8087 * Significant at the 0.05 probability level 95 Table A15. Analysis of variance for pleated germination and cold test results for Exp. 3 (Seed Enhancement), 1999 as influenced by treatment, time of count, and replication. Pleated Test mm M £1! ELM BEE M199 EJZE Treatment 4 12.49 0.0002" 7.40 0.0030" Time 1 47.66 <.0001" 9.14 0.0106" Rep 3 1 .31 0.3155 0.60 0.6297 Treat"Time 4 2.37 0.1110 1.29 0.3294 " Significant at the 0.05 probability level Table A16. Multiple comparison and mean separation for the conductivity test in Exp. 2 (Seed Size). Variety Size LSMEAN SE OF t Pr>|t| LetGrp ACH648 2 621.78 17.94 18 64.65 0.0001 A ACH648 3 525.23 17.94 18 29.27 0.0001 8 ACH648 4 459.72 17.94 18 25.62 0.0001 C ACH503 2 653.69 17.94 18 36.43 0.0001 A ACH503 3 535.47 17.94 18 29.84 0.0001 8 ACH503 4 507.13 17.94 18 28.26 0.0001 8 ACH555 2 462.75 17.94 18 25.79 0.0001 A ACH555 3 403.81 17.94 18 22.50 0.0001 B ACH555 4 398.85 17.94 18 22.23 0.0001 8 Table A1 7. Multiple comparison and mean separation for the different planting dates and stand counts conducted in Exp. 3 (Seed Enhancement), 1998. TLANTITIG TMT DAP LSMEAN sE [TIE t Pr>|t| LetGrp Early Celpril 1 1 0.45 2.69 390 0.17 0.8686 8 Early PAT 11 19.33 2.69 390 7.19 0.0001 A Early PATACH 1 1 5.44 2.69 390 2.03 0.0435 8 Early Plain 1 1 2.1 1 2.69 390 0.79 0.4325 8 Early TACH 1 1 1 .1 1 2.69 390 0.41 0.6794 8 Early Celpril 13 11.34 2.69 390 4.22 0.0001 0 Early PAT 13 40.33 2.69 390 15.01 0.0001 A Early PATACH 13 27.22 2.69 390 10.13 0.0001 8 Early Plain 13 19.44 2.69 390 7.23 0.0001 C Early TACH 13 12.67 2.69 390 4.71 0.0001 CD Early Celpril 16 20.33 2.69 390 7.57 0.0001 D Early PAT 16 46.11 2.69 390 17.16 0.0001 A Early PATACH 16 29.78 2.69 390 1 1 .08 0.0001 BC Early Plain 16 34.33 2.69 390 12.77 0.0001 8 Eany TACH 16 26.22 2.69 390 9.76 0.0001 CD Early Celpril 19 32.22 2.69 390 11 .99 0.0001 C Eany PAT 19 50.22 2.69 390 18.69 0.0001 A Early PATACH 19 38.45 2.69 390 14.30 0.0001 BC Early Plain 19 44.56 2.69 390 16.58 0.0001 AB Eafly TACH 19 40.33 2.69 390 15.01 0.0001 8 Early Celpril 22 48.11 2.69 390 17.90 0.0001 8 Early PAT 22 57.89 2.69 390 21.54 0.0001 A Early PATACH 22 45.55 2.69 390 16.95 0.0001 8 Early Plain 22 58.89 2.69 390 21.91 0.0001 A Early TACH 22 50.22 2.69 390 18.69 0.0001 8 97 Table A 17. Cent. PLANTING TMT DAP LSMEAN 5? DP; t Pr>|t| LetGrp Early Celpril 28 49.67 2.69 390 18.48 0.0001 6 Early PAT 28 57.56 2.69 390 21.41 0.0001 A Early PATACH 28 49.45 2.69 390 18.40 0.0001 B Early Plain 28 59.89 2.69 390 22.28 0.0001 A Early TACH 28 53.22 2.69 390 19.80 0.0001 Ae Early Celpril 44 47.67 2.69 390 17.74 0.0001 c Early PAT 44 58.33 2.89 390 20.96 0.0001 AB Early PATACH 44 49.22 2.69 390 18.31 0.0001 ec Early Plain 44 58.22 2.69 390 21.66 0.0001 A Early TACH 44 54.67 2.69 390 20.34 0.0001 ABC Early Celpril 49 45.89 2.69 390 17.07 0.0001 c Early PAT 49 54.44 2.69 390 20.26 0.0001 AB Early PATACH 49 48.89 2.69 390 18.19 0.0001 BC Early Plain 49 54.11 2.69 390 20.13 0.0001 AB Early TACH 49 53.78 2.69 390 20.01 0.0001 AB Late Celpril 19 2.58 2.69 390 0.95 0.3427 B Late PAT 19 10.78 2.69 390 4.01 0.0001 A Late PATACH 19 5.22 2.69 390 1.94 0.0528 AB Late Plain 19 5.78 2.69 390 2.15 0.0322 A6 Late TACH 19 1.89 2.69 390 0.70 0.4827 6 Late Celpril 24 3.89 2.69 390 1.45 0.1488 6 Late PAT 24 12.11 2.69 390 4.51 0.0001 A Late PATACH 24 7.89 2.69 390 2.94 0.0035 AB Late Plain 24 7.00 2.69 390 2.60 0.0096 AB Late TACH 24 3.89 2.69 390 1.45 0.1488 6 98 Table A 17. Cont. _PLANTTNG fifi bAP LSMEAN SE OF t Pr>|t| Letcrp Late Celpril 31 27.45 2.69 390 10.21 0.0001 A Late PAT 31 28.58 2.69 390 1062 0.0001 A Late PATACH 31 28.00 2.69 390 10.42 0.0001 A Late Plain 31 28.89 2.89 390 10.75 0.0001 A Late Proprim 31 34.78 2.69 390 12.94 0.0001 A Late TACH 31 27.56 2.69 390 10.25 0.0001 A Late Celpril 34 22.22 2.69 390 8.27 0.0001 B Late PAT 34 24.45 2.69 390 9.09 0.0001 AB Late PATACH 34 22.33 2.69 390 8.31 0.0001 8 Late Plain 34 25.33 2.69 390 9.43 0.0001 AB Late Proprim 34 30.45 2.69 390 11.83 0.0001 A Late TACH 34 20.22 2.69 390 7.52 0.0001 6 Late Celpril 38 26.34 2.69 390 9.80 0.0001 A Late PAT 38 26.45 2.69 390 9.84 0.0001 A Late PATACH 38 25.11 2.69 390 9.34 0.0001 A Late Plain 38 27.45 2.69 390 10.21 0.0001 A Late Proprim 38 29.56 2.69 390 11.00 0.0001 A Late TACH 38 22.89 2.69 390 8.52 0.0001 A 99 Table A18. Multiple comparison and mean separation for the different sites and stand counts conducted in Exp. 3 (Seed Enhancement), 1999. fiT‘E WT DAP LSMEAN sE DF t Pr>|t| LetGrp Low Celpril 9 70.75 4.91 195 14.41 0.0001 A Low PAT 9 75.25 4.91 195 15.32 0.0001 A Low PATACH 9 68.00 4.91 195 13.85 0.0001 A Low Plain 9 78.25 4.91 195 15.94 0.0001 A Low TACH 9 74.25 4.91 195 15.12 0.0001 A Low Celpn‘l 14 70.50 4.91 195 14.36 0.0001 A Low PAT 14 73.50 4.91 195 14.97 0.0001 A Low PATACH 14 66.00 4.91 195 13.44 0.0001 A Low Plain 14 78.25 4.91 195 15.94 0.0001 A Low TACH 14 76.25 4.91 195 15.53 0.0001 A Low Celpril 17 70.75 4.91 195 14.41 0.0001 A Low PAT 17 70.75 4.91 195 14.41 0.0001 A Low PATACH 17 65.75 4.91 195 13.39 0.0001 A Low Plain 17 78.75 4.91 195 16.04 0.0001 A Low TACH 17 75.75 4.91 195 15.43 0.0001 A Low Celpril 21 70.00 4.91 195 14.26 0.0001 AB Low PAT 21 69.25 4.91 195 14.10 0.0001 AB Low PATACH 21 64.50 4.91 195 13.14 0.0001 B Low Plain 21 78.75 4.91 195. 16.04 0.0001 A Low TACH 21 75.50 4.91 195 15.38 0.0001 AB Medium Celpril 9 49.00 4.91 195 9.98 0.0001 A Medium PAT 9 41.50 4.91 195 8.45 0.0001 A Medium PATACH 9 25.25 4.91 195 5.14 0.0001 B Medium Plain 9 50.50 4.91 195 10.28 0.0001 A Medium TACH 9 37.25 4.91 195 7.59 0.0001 AB Medium Celpril 14 57.75 4.91 195 11.76 0.0001 AB Medium PAT 14 45.75 4.91 195 9.32 0.0001 BC Medium PATACH 14 32.25 4.91 195 8.57 0.0001 c Medium Plain 14 60.00 4.91 195 12.22 0.0001 A Medium TACH 14 49.50 4.91 195 10.08 0.0001 AB 100 Table A18. Cont. sfi TMT DAP LsM'EAN s? DF t Pr>|t| LetGrp Medium Celpril 17 59.25 4.91 195 12.07 0.0001 A Medium PAT 17 44.50 4.91 195 9.06 0.0001 BC Medium PATACH 17 32.25 4.91 195 6.57 0.0001 c Medium Plain 17 60.00 4.91 195 12.22 0.0001 A Medium TACH 17 50.00 4.91 195 10.18 0.0001 AB Medium Celpril 21 63.50 4.91 195 12.93 0.0001 A Medium PAT 21 45.75 4.91 195 9.32 0.0001 ec Medium PATACH 21 33.50 4.91 195 6.82 0.0001 c Medium Plain 21 62.50 4.91 195 12.73 0.0001 A Medium TACH 21 51.50 4.91 195 10.49 0.0001 AB High Celpril 9 54.00 4.91 195 11.00 0.0001 8 High PAT 9 58.50 4.91 195 11.91 0.0001 AB High PATACH 9 66.50 4.91 195 13.54 0.0001 AB High Plain 9 68.25 4.91 195 13.90 0.0001 A High TACH 9 66.25 4.91 195 13.49 0.0001 AB High Celpril 14 46.75 4.91 195 9.52 0.0001 AB High PAT 14 39.00 4.91 195 7.94 0.0001 8 High PATACH 14 58.25 4.91 195 11.86 0.0001 A High Plain 14 47.50 4.91 195 9.67 0.0001 AB High TACH 14 53.50 4.91 195 10.90 0.0001 A High Celpril 17 26.75 4.91 195 5.45 0.0001 BC High PAT 17 23.00 4.91 195 4.68 0.0001 c High PATACH 17 52.25 4.91 195 10.64 0.0001 A High Plain 17 31.00 4.91 195 6.31 0.0001 60 High TACH 17 38.50 4.91 195 7.84 0.0001 B High Celpril 21 14.75 4.91 195 3.00 0.0001 B High PAT 21 14.75 4.91 195 3.00 0.0001 a High PATACH 21 41.00 4.91 195 8.35 0.0001 AB High Plain 21 20.25 4.91 195 4.12 0.0001 B 101 Table A19. Daily maximum and minimum soil temperatures (°C) and precipitation (mm) at the three field testing locations in 1998. Misteguay Metea Kilmanafl Date m. ML 2m.- M m. 0m M... MLn. 01m 04/01 10.2 8.2 3.8 13.3 12.2 19.6 16.1 3.9 28.2 04/02 8.4 7.3 0.8 12.8 10.0 9.9 16.1 3.9 5.8 04/03 7.3 6.3 8.9 8.9 0.8 6.7 2.8 1.3 04/04 8.7 5.3 7.2 9.4 0.5 7.2 1.1 04/05 9.2 4.4 8.3 6.1 7.8 -1.7 04/06 9.7 4.5 9.4 6.7 7.2 -50 04/07 10.1 5.4 10.0 7.2 11.1 -50 04/08 8.9 6.8 6.9 10.0 8.3 10.2 12.8 0.0 04/09 6.8 6.0 6.1 8.3 4.1 5.0 3.9 7.1 04/10 9.0 4.5 8.9 6.7 5.3 8.3 0.6 04/11 9.9 4.7 7.8 6.1 8.3 -50 04/12 10.4 6.4 10.0 7.2 15.6 -50 04/13 11.4 8.3 11.1 8.3 20.6 4.4 04/14 11.5 9.9 1.3 10.6 9.4 0.8 21.1 9.4 T 04/15 10.8 8.7 11.1 10.6 2.5 12.8 3.3 8.9 04/16 11.3 8.1 13.2 10.6 10.0 1.0 10.0 2.2 04/17 10.4 7.4 11.7 10.0 7.4 16.7 1.1 13.7 04/18 11.3 6.2 10.6 8.9 0.5 9.4 1.7 04/19 11.8 8.1 11.1 8.9 17.2 3.3 04/20 12.8 7.6 11.1 9.4 13.3 0.6 04/21 12.6 8.8 12.2 9.4 16.1 ' 0.6 04/22 14.3 8.9 12.2 11.1 16.1 1.7 04/23 14.9 9.3 13.3 11.1 17.8 1.7 04/24 14.2 10.2 13.3 10.6 18.9 2.2 04/25 13.1 9.2 13.3 11.1 17.2 1 1 04/26 11.9 9.4 13.3 10.6 24.1 10.0 1.7 04/27 11.8 6.8 12.2 9.4 10.2 4.4 -1.7 04/28 13.1 6.9 12.2 8.9 9.4 -3.9 04/29 12.0 8.3 13.3 9.4 15.6 -3.3 04/30 13.7 10.2 1.5 12.8 10.6 0.3 16.7 0.6 T 05/01 15.5 12.3 13.3 12.8 17.3 21.1 8.3 05/02 14.3 12.4 15.6 13.3 21.8 16.7 9.4 8.1 05/03 15.2 11.6 11.7 11.7 1.5 13.9 7.2 1.5 05/04 15.9 11.6 15.0 14.4 1.3 20.0 7.2 05/05 16.9 11.7 16.7 13.9 2.5 21.1 7.8 05l06 17.7 13.8 17.2 13.9 23.9 9.4 0.5 05/07 17.9 14.6 18.3 15.6 25.0 10.6 1.8 05I08 16.8 14.8 26.9 18.3 16.7 0.3 23.3 10.6 05/09 16.5 13.4 8.9 17.2 15.6 1.3 18.3 7.2 05/10 17.2 12.4 18.3 15.6 15.6 6.1 05/11 15.9 13.8 17.8 15.0 20.6 6.1 2.5 05112 18.3 14.2 17.2 15.6 1.8 14.4 11.7 4.1 05/13 19.1 15.3 17.8 15.0 2.3 17.8 12.2 05/14 21.2 15.2 19.4 16.1 25.0 9.4 05/15 21.8 16.1 21.1 16.7 26.7 10.0 05/16 21.2 18.5 21.7 18.9 31.7 15.6 102 Table A19. Cont. Misteguay Metea Kilmanagh E112 M. m 2010. M. 1m 0m. MA. M10. 2180.. 05117 21.3 16.4 21.7 18.9 27.2 15.6 05118 21.3 16.8 21.7 18.9 27.8 13.9 T 05119 22.2 17.6 21.7 18.9 31.1 15.0 05120 21.9 17.8 22.2 18.9 32.2 12.8 0.5 05121 20.1 16.3 22. 2 19.4 25.6 8.9 05122 18.8 14.4 21.7 18.3 15.0 2.2 05123 19.0 13.5 21.1 17.2 17.2 2.8 05124 17.4 14.3 2.5 21.1 16.7 21.1 5.6 05125 15.6 14.3 4.8 18.3 17.8 3.8 22.8 11.1 3.6 05126 19.2 12.4 17. 8 15. 6 0.3 17.2 9.4 9.4 05127 20.4 14.6 20. 6 15. 0 19.4 7.2 05128 19.8 15.7 21. 7 17. 8 26.1 10.0 05129 20.7 17.4 0.8 21.1 18.3 28.3 15.0 1.8 05130 21.4 16.4 21.7 19.4 26.7 7.2 05131 19.8 18.2 5.8 23.3 19.4 15.2 22.8 10.0 0.5 06/01 19.4 14.2 22.8 18.3 23.3 2.8 2.0 06102 19.1 16.3 22.2 18.3 20.0 5.6 06103 17.6 14.2 21.7 17.8 26.1 5.0 06104 17.6 12.9 19.4 16.1 15.6 3.9 T 06105 16.2 13.1 19.4 16.1 17.8 1.1 06106 15.4 12.3 17.8 15.6 13.9 3.3 06107 16.6 12.4 16.7 15.0 15.6 7.2 0.3 06108 17.9 12.4 17.8 15.0 17.2 3.9 06109 16.5 13.9 1.0 18. 9 15. 0 19.4 3.9 06110 15.7 14.3 5.8 17. 8 16. 1 9.4 21.1 10.0 T 06111 17.2 14.9 5.6 18.3 16.1 0.5 19.4 12.2 0. 5 06112 19.9 16.8 1.0 18.3 16.7 7.1 22.2 14.4 18. 3 06113 19.4 16.9 2.5 22.2 18.3 9.4 27.2 14.4 06114 21.6 16.1 21.7 18. 9 0.5 19.4 12.2 3.6 06115 23.3 17.3 1.3 22. 8 18. 9 24.4 11. 1 06116 23.4 18.6 24. 4 20.6 1.8 24.4 12. 8 06117 23.7 19.1 24.4 21.7 3.6 25.0 14.4 06118 24.7 18.9 24.4 21.1 25.0 13.9 06119 24. 1 20.7 25.0 21.1 26. 1 16.1 1.8 06120 25.4 19.8 26. 1 22.8 31.1 17. 8 06121 25.1 21.1 4.3 26. 1 22. 2 32. 2 18. 9 6.1 06122 25.8 20.3 26.1 23. 3 28.9 19.4 06123 26. 7 22.1 0.5 26.7 23.3 30.0 15.6 06124 26.3 21.8 27.8 25.0 32.8 16.7 06125 26. 9 23.0 27.2 24.4 8.9 33. 9 19.4 06126 27.3 23.7 27.8 23.9 20.8 33.9 16.7 06127 25.7 22.2 5.8 27.8 24.4 1.3 26.7 16.1 1.0 06128 26.5 21.7 26. 7 24. 4 30.0 17.8 06129 26.6 21.7 26. 7 24. 4 0.3 31.7 15. 6 12.2 06130 25.1 22.7 27.8 23.9 0.3 30.0 15. 6 103 Table A20. Daily maximum and minimum soil temperatures ("0) and precipitation (mm) at the three field testing locations in 1999. Mistegiay Metea Date MAX.- Min. 221.0. Mags MEL 020 04101 9.3 8.1 11.0 8.9 04102 10.9 8.4 13.4 9.7 04103 12.8 9.4 15.0 11.3 18.8 04104 12.3 7.9 10.4 13.4 9.5 17.0 04105 9.5 6.6 12.1 7.5 0.3 04106 8.9 7.3 0.8 11.3 8.2 0.3 04107 10.3 6.0 0.3 13.3 6.5 04108 12.6 7.7 15.8 8.9 1.5 04109 11.3 7.4 4.8 12.0 6.8 23.4 04110 8.9 5.4 11.1 5.1 04111 8.1 5.4 21.6 8.0 6.3 7.9 04112 8.8 4.3 11.9 4.9 04113 10.6 4.9 12.5 5.8 04114 11.7 5.9 13.8 6.2 04115 10.4 7.6 10.3 7.9 04116 8.9 7.2 15.0 9.3 7.8 12.7 04117 8.9 6.1 3.6 10.1 7.1 1.3 04118 8.3 6.5 0.8 10.4 7.1 1.3 04119 8.8 6.0 10.9 6.6 2.0 04120 11.0 6.3 12.7 8.0 0.5 04121 9.9 8.0 11.8 9.2 04122 9.3 8.1 39.9 10.9 9.1 50.0 04123 8.1 6.6 17.0 9.1 6.6 27.4 04124 9.5 4.6 11.3 4.8 04125 10.8 5.4 12.9 6.0 04126 12.3 7.1 13.9 7.6 04127 11.4 8.1 13.3 9.0 04128 11.7 7.9 13.6 8.5 04129 12.2 8.1 13.8 8.7 04130 13.1 7.7 14.7 8.5 05101 14.4 8.7 13.3 11.1 05102 14.9 9.8 13.9 10.0 05103 15.8 10.7 14.4 12.8 05104 16.7 11.7 14.4 12.8 05105 15.6 12.9 0.5 15.0 13.9 05106 15.0 13.8 1.3 17.2 15.0 0.3 05107 14.8 12.2 16.1 15.0 1.3 05108 14.2 12.5 3.3 16.1 15.0 05109 14.9 10.7 15.6 13.9 1.0 05110 15.3 10.8 13.9 13.9 05111 15.6 11.2 14.4 13.3 05112 14.4 11.4 5.8 05113 13.3 10.1 15.0 13.3 2.0 05114 14.9 9.8 14.4 13.3 05115 15.7 12.5 1.8 13.9 12.8 104 Table A20. Cont. 05116 0511 7 0511 8 0511 9 05/20 05121 05122 05123 05124 05125 05126 05127 05128 05129 05130 05/31 06101 06102 06103 06104 06105 06106 06107 06108 06109 0611 0 0611 1 0611 2 0611 3 06114 0611 5 0611 6 0611 7 06/1 8 0611 9 06120 06/21 06122 06123 06124 06125 06126 06127 06128 06129 06130 Misteguay 16.9 13.4 5.6 18.8 15.3 8.6 17.6 16.3 3.0 17.3 13.5 18.7 12.9 18.7 15.1 17.8 15.8 1.3 16.3 13.4 17.3 15.1 12.3 12.3 11.1 1.8 15.8 10.7 17.6 11.2 19.7 13.4 21.2 15. 2 21.6 17. 0 20.3 18.2 1.3 22.0 18.2 2.5 20.7 18.6 5.3 19.7 16.0 20.3 15.0 21.9 16.9 24. 3 19.8 24.2 20.8 24. 7 20.3 1.0 23. 4 20.3 25.8 20.4 26.2 22.0 25.9 22.0 5.3 24. 7 21.7 8.4 22. 3 20.1 9.9 20. 9 16.6 20.7 17.5 21.2 16.9 1.0 22.5 16. 4 22.0 18.0 22.8 18.3 24. 1 18.6 23. 9 19. 1 24.3 20. 2 23.3 21.6 26.2 20.1 26.3 21.3 25 22.3 25.8 21.9 24.8 20. 9 22.9 19.9 105 Metea M 15.6 16.1 20.0 18.9 18.9 18. 9 18. 9 19. 4 17.2 16.1 13.3 16.1 16.7 18.9 18. 9 19. 4 20.0 21.1 21.1 18.4 21.3 24.5 25. 2 25. 6 24.6 26. 6 26. 9 26.8 24.7 23.3 21.8 20.8 21.2 24.1 23.1 24.8 25.6 25.2 26. 2 24. 5 26.8 27.1 25.8 27.3 24.7 22.7 Mill. 15.6 12.2 16.1 17.2 16.7 16.1 17.2 17.2 16.1 19.5 020. 8.9 18.5 1.3 7.6 0.3 2.8 0.3 0.5 6.6 8.9 0.5 REFERENCES 106 Akeson, W. 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